Castro - Divisadero Tree Tour (2-15-25)

February 18, 2025 by Michael Sullivan

A busy thoroughfare, a quiet residential street, a dead-end road, and a schoolyard filled with native plants—all this in today’s tree walk. We have dubbed this neighborhood Castro-Divisadero, as it incorporates the triangle at the merging of Castro and Divisadero streets. It falls just beyond the Castro, Duboce Triangle, Corona Heights Park, Buena Vista Park, and Haight neighborhoods. Some surprisingly mature trees can be found along the way.

Today’s walk begins at the main entrance to the McKinley Elementary School, 1025 14th Street. It heads east on 14th to Castro Street, then south along Castro to Henry Street. It continues west for half a block on Henry before returning to and crossing Castro, then north on the east side of Castro to Duboce Avenue. At Duboce, it crosses Castro and continues north on the west side of Castro to it’s merger with Divisadero Street. From there, it heads south on Divisadero to the end of Divisadero at 14th. The walk is a bit over a mile in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 42. White arrows on the pavement provide directions whenever a turn is needed.

The street addresses provided below will help when the chalk has faded. Many of the first trees on this walk are planted around the outer edges of the McKinley Elementary School playground (noted as McKinley below); some are planted around the Davies Hospital campus (noted as Davies below); others are planted in sidewalk pockets; and a few are planted within the front or rear gardens of homes along the route.

14th Street, Divisadero to Castro, south side

1. 1025 - 14th Mayten (Maytenus boaria), Chile (many trees along 14th Street, with gracefully pendant branches, resembling those of weeping willows)

**Head down the steps or the ramp towards the school building**

2. 1025 - 14th Santa Cruz Island ironwood (Lyonothamnus floribundus ssp. aspleniifolius), CA’s Channel Islands, except Catalina Island

3. McKinley Owlswood Blue ceanothus (Ceanothus arboreus x thyrsiflorus ‘Owlswood Blue’), hybrid of California native species

Blackwood acacia (Acacia melanoxylon), SE Australia (young tree with unusually rounded phyllodes)

Meyer lemon (Citrus x meyeri), hybrid of mandarin and pomelo, both SE Asian species

4. McKinley Toyon (Heteromeles arbutifolia), CA and SF native! (birds have already eaten the brightly colored fruits for which this small tree is known; commonly seen in natural areas in SF, particularly the Presidio and Bay View Hill.

5. McKinley Coast redwood (Sequoia sempervirens), Big Sur to SW Oregon; CA coastal native (this species is the tallest tree in the world)

6. McKinley California buckeye (Aesculus californica), California & Oregon; a San Francisco native tree! (it’s just leafing out)

Castro Street, 14th to Henry, west side

7. McKinley Southern magnolia (Magnolia grandiflora), SE USA (this species was planted extensively along Castro Street, on both sides, from here to Market Street; the largest trees, south of Henry Street, were planted in the early 70s)

8. McKinley African fern pine (Afrocarpus falcatus, formerly A. gracilior), E & S Africa

9. McKinley Sydney golden wattle (Acacia longifolia), E Australia (this species was used extensively in the early plantings of Golden Gate Park)

Henry Street, west of Castro, north side

10. McKinley Torrey pine (Pinus torreyana), San Diego County, and Santa Rosa Island, CA (this long-needled pine, though adaptable in cultivation, is the rarest pine species in the world, found only on the coast near La Jolla and Del Mar, and on Santa Rosa Island off Santa Barbara; these are among the largest specimens in SF)

11. McKinley Canary Island pine (Pinus canariensis), Canary Islands (surprisingly uncommon in SF, these pines have even longer needles than the Torrey pines nearby)

12. McKinley London plane tree (Platanus x hispanica), hybrid of E USA species and Mediterranean species (this deciduous tree is among the most commonly planted trees in cities around the world outside the tropics)

Henry Street, west of Castro, south side

13. 265 Henry Peppermint willow (Agonis flexuosa), SW Australia

14. 150 Castro Incense cedar (Calocedrus decurrens), CA native; Oregon to Baja (tree is in the rear garden on Henry; the wood is used in construction and for making pencils)

15. 150 Castro Avocado tree (Persea americana), Mexico & Central America (tree is in the rear garden on Henry)

***Cross Castro carefully at the crosswalk; note the rows of Southern Magnolia stretching along Castro to the south***

Henry Street, east of Castro, south side

16. 197 Henry Ginkgo (Ginkgo biloba), China (these distinctive deciduous trees are the last of an ancient lineage of gymnosperms)

Henry Street, east of Castro, north side

17. 149 Castro Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (row of 3 trees on Henry; first introduced in San Francisco)

Castro Street, 14th to Duboce, east side

18. Davies Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA, native (one of the most widely planted conifers in coastal California; numerous mature trees border the Davies Hospital parking garage)

19. Davies Monterey pine (Pinus radiata), CA native: Año Nuevo, Monterey, Cambria, plus Cedros and Guadalupe islands, MX (several can be seen mixed with the Monterey pines around the parking garage; most widely planted coniferous tree in the world, mostly for lumber)

20. 60 Castro Sweetgum (Liquidambar styraciflua), E USA to Mexico & Central America (across the street; this tallest tree on the block is holding onto last year’s leaves, which will drop as this year’s leaves emerge)

21. 36 Castro Brisbane box (Lophostemon confertus), E Australia (this block of Castro is lined with this species, most planted at the time of the construction of Davies Hospital in the 1960s; some are among the largest in the city)

***Cross Castro at the traffic signal***

Castro Street at Duboce, west side

22. 2 Castro Blackwood acacia (Acacia melanoxylon), SE Australia (this young tree, situated far too close to the building, is likely a seedling of the mature specimen a few yards uphill on Duboce)

Castro Street, Duboce to Divisadero, west side

23. 754 Duboce Lombardy poplar (Populus nigra ‘Italica’), a narrow-growing cultivar of a Eurasian species (2 deciduous trees in the corner bed)

24. 754 Duboce Brush cherry (Syzygium australe, formerly S. paniculatum), E Australia

a sidewalk square from 1931! (across from the silk oak near where Castro and Divisadero meet)

25. 9-11 Castro Silk oak (Grevillea robusta), E Australia (across the street, in the walled yard to the south of the building; known for their bright yellow orange flowers in late spring in areas with a warmer climate, these two trees seldom flower due to the chill of the city)

Divisadero Street, Castro to Duboce, east side

26. 170 Divisadero Hollywood juniper (Juniperus chinensis ‘Torulosa’ or ‘Kaizuka’), E Asia

27. 170 Divisadero Olive (Olea europaea), Mediterranean Basin

28. 154 Divisadero Chinese windmill palm (Trachycarpus fortunei), China (3 trees)

29. 154 Divisadero Water gum (Tristaniopsis laurina), E Australia (this tree grows in stream-side locations in the wild, hence the common name; SF’s most commonly planted street tree)

30. 140 Divisadero Ponytail palm (Beaucarnea guatemalensis), Central America (a rare species in cultivation, particularly in SF)

31. 140 Divisadero Hybrid pōhutukawa in Māori (Metrosideros excelsa x kermadecensis), New Zealand mainland and Kermadec Islands (the rounded leaves, relatively few aerial roots, and winter flowers suggest that this tree is a hybrid)

32. 126 Divisadero Peruvian pepper tree (Schinus molle), Peru, Brazil, & Chile

33. 108 Divisadero Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia (these heat loving trees are becoming more common in SF, especially in warmer areas of the city—all thanks to climate change)

Duboce Avenue, Divisadero to Castro, north side

34. 760 Duboce Willow-leaf peppermint (Eucalyptus nicholii), SE Australia (2 trees, mid-block on Duboce)

35. 106 Divisadero Japanese black pine (Pinus thunbergii), Japan and S Korea (tree is on Duboce at the corner)

Divisadero Street, Duboce to 14th, west side

36. 99 Divisadero Tree fuchsia (Fuchsia arborescens), C America (this large shrubby fuchsia flowers all year in SF)

37. 99 Divisadero Hercules tree aloe (Aloidendron ‘Hercules’), hybrid of two S African species (note the diverse plantings in this garden designed by the talented Dan Carlson)

38. 67 Divisadero Purple-leaf plum (Prunus cerasifera), Eurasia (pink flowers usually appear by February; formerly SF’s most planted street tree; usually without leaves through fall and winter)

39. 61 Divisadero Hybrid hibiscus (Hibiscus rosa-sinensis), tropical Asia (not known to thrive in SF’s cool climate, but this specimen is doing well in a protected corner of the building)

40. 55 Divisadero Thornless honey locust (Gleditsia triacanthos ‘Inermis’), E USA

41. 42 Divisadero Indian laurel fig (Ficus microcarpa ‘Nitida’), S Asia to N Australia (the entire block, from here to 14th, is planted on both sides with this tree; formerly one of SF’s most planted trees)

42. 16 Divisadero Bailey’s acacia (Acacia baileyana), E Australia (this is usually among the earliest flowering trees in SF, always beginning in January with fluffy bright yellow flowers, which are now done on this fine specimen)

The tour ends here, just a few yards from its start at McKinley Elementary School.

Oceanside Walking Tour

January 28, 2025 by Michael Sullivan

On yet another mild, dry winter day (will it ever rain again this season?), we visited the neighborhood known as Oceanview, in the southwestern quadrant of San Francisco. This is a densely built neighborhood, with houses close to the street, leaving little room for street trees. Fortunately, the neighborhood benefits from the trees that surround the Millie & Lovie Ward Recreation Center, which fills the block bounded by Plymouth and Capitol avenues and Montana and Lobos streets. The mature Monterey cypresses on the west, south, and east sides of the Rec Center are among the healthiest in the city, undoubtedly due to the extra rain and fog typical in this section of the Alemany Gap.

A delightful surprise, to those of us not from the neighborhood, was the planted median on the long block of Minerva Street, just west of Plymouth; it’s filled with a variety of small trees and palms, flowering shrubs, succulents, and art.

It was encouraging to note that Friends of the Urban Forest (FUF) has been planting young street trees throughout the neighborhood, wherever sidewalk space permitted. This is part of a concerted effort on the part of both the city’s Urban Forestry Division and FUF to provide more shade in areas of the city that have typically lacked tree cover. With a warming climate, the importance of trees to provide shade and cool the environment cannot be stressed enough.

Today’s walk begins at the main entrance to the Millie & Lovie Ward Recreation Center at Capitol Avenue (cross is Minerva Street). It heads south on Capitol just past Lobos Street, then returns to Lobos and heads east to Plymouth Avenue, and north on Plymouth. At Minerva Street, the walk heads east up the gentle part of the hill to about midway, crosses the median at the red steps, and returns to Plymouth. It then continues north on Plymouth, west on Montana Street, and finally south on Capitol to the beginning of the walk at Minerva. This walk is about 1 mile in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 32. White arrows on the pavement provide directions whenever a turn is needed.

Capitol Avenue, Minerva to Lobos, east side

1. Rec Ctr Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA, native (opposite 545 Capitol; one of the most widely planted conifers in coastal California; mature trees surround the Rec Ctr on the west, south, and east)

2. Rec Ctr Jester conebush (Leucadendron ‘Jester’), hybrid of S African species (corner of Capitol & Lobos and Plymouth & Lobos

Capitol Avenue, south of Lobos, east side

3. 438 Capitol Eureka lemon tree (Citrus x limon ‘Eureka’) hybrid of S Asia species (not commonly grown in SF)

4. 438 Capitol Southern magnolia (Magnolia grandiflora), SE USA

**Cross the street carefully**

Capitol Avenue, south of Lobos, west side

5. Corner school grounds Hybrid pōhutukawa in Māori (Metrosideros excelsa x kermadecensis), New Zealand mainland and Kermadec Islands (opposite 438 Capitol; the rounded leaves, relatively few aerial roots, and winter flowers suggest that this tree is a hybrid)

Lobos Street, Capitol to Plymouth, south side

6. 177 Lobos Brisbane box (Lophostemon confertus), E Australia

**Cross the street carefully**

Lobos Street, Capitol to Plymouth, north side

7. Rec Ctr Peppermint willow (Agonis flexuosa), SW Australia (opposite 171 Lobos)

8. Rec Ctr Santa Cruz Island ironwood (Lyonothamnus floribundus ssp. aspleniifolius), CA’s Channel Islands, except Catalina Island (opposite 171 Lobos; a number of these native trees have been planted on the slope above the sidewalk)

9. Rec Ctr Cajeput tree (Melaleuca quinquenervia), New Caledonia, New Guinea, NE Australia (opposite 159 Lobos)

10. Rec Ctr Holm oak (Quercus ilex), Mediterranean Basin (several trees opposite 151 Lobos; a surprisingly uncommon tree in SF, despite its adaptability to our climate;

11. Rec Ctr Water gum (Tristaniopsis laurina), E Australia (opposite 139 Lobos; this tree grows in stream-side locations in the wild, hence the common name; SF’s most commonly planted street tree)

12. Rec Ctr Bronze loquat (Eriobotrya deflexa, syn. Rhaphiolepis deflexa), S China and Vietnam (opposite 131 Lobos)

13. Rec Ctr Coast live oak (Quercus agrifolia), SF and CA native; Baja to Mendocino, always within 50 miles of the coast (2 trees opposite 119 Lobos; though native to SF, these specimens are not thriving as well as the nearby Holm oaks)

14. Rec Ctr Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (corner Lobos & Plymouth; first introduced in San Francisco; larger ones are around the corner on Plymouth)

Plymouth Avenue, Lobos to Minerva, west side

15. Rec Ctr Olive (Olea europaea), Mediterranean Basin (opposite 512 Plymouth)

Minerva Street median, east of Plymouth, south side

16. Median Coast blueblossom (Ceanothus thyrsiflorus), coastal S Oregon to CentralCalifornia; a San Francisco native (opposite 554 Plymouth)

17. Median Red-tip photinia (Photinia x fraseri), hybrid (opposite 88 Minerva; more commonly seen as a dense shrub with red new foliage along CA freeways)

18. Median Mexican fan palm (Washingtonia robusta), S Baja & Sonora, Mexico (opposite 85 Minerva)

19. Median Pink melaleuca (Melaleuca nesophila), W Australia (opposite 71 Minerva)

20. Median Giant yucca (Yucca gigantea, formerly Y. elephantipes), Mexico & Central America (opposite 63 Minerva)

21. Median Torch aloe (Aloe arborescens), S & SE Africa (opposite 57 Minerva; though the scientific name suggests that this is “tree-like”, it rarely is more than a big shrub; notable for its reliable flowering during CA winters)

22. Median Mediterranean fan palm (Chamaerops humilis), W Mediterranean Basin: Portugal & Morocco to Tunisia & Italy (opposite 55 Minerva; this is a young specimen that will grow into a low multi-trunked tree; it has the northernmost natural range of any palm in the world)

**Cross to north side of Minerva, using the red concrete steps; watch the traffic**

Minerva Street median, east of Plymouth, north side

23. Median Red escallonia (Escallonia rubra), S Chile and Argentina, all the way to Tierra del Fuego (opposite 30 Minerva; normally grown as a dense large shrub, this one has been pruned into an attractive multi-trunk tree)

24. Median Cabbage tree or tī kōuka in Māori (Cordyline australis), New Zealand (opposite 36 Minerva)

25. Median Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA, native (opposite 80 Minerva; this tree is only about 10 years old; compare with the mature trees around the Rec Ctr)

Plymouth Avenue, Minerva to Montana, east side

26. 668 Plymouth African fern pine (Afrocarpus falcatus, formerly A. gracilior), E & S Africa

Montana Street, Plymouth to Capitol, south side

27. Rec Ctr Pussy willow (Salix sp.), California (opposite 136 Montana; the flowers, resembling the paws of a kitten, will appear soon)

28. Rec Ctr Saratoga laurel (Laurus ‘Saratoga’), hybrid of Mediterranean and Atlantic species (opposite 148 Montana; several trees inside the fence; a selected form introduced by Saratoga Horticultural Foundation)

Montana Street, Plymouth to Capitol, north side

29. 158 Montana Angel’s trumpet (Brugmansia ‘Charles Grimaldi’), Andes (tree is across the street, with large pendant, trumpet-like flowers; named for the late, well-known garden designer in SF)

30. 194 Montana Island oak (Quercus tomentella), California’s Channel Islands (a CA native) and Guadalupe Island, Mexico (this young tree represents a new species introduction that should thrive in the city’s climate)

Capitol Avenue, Montana to Minerva, west side

31. 201 Capitol Japanese camellia (Camellia japonica), E Asia (though usually grown as a shrub for its beautiful late winter/spring flowers, Japanese camellia is actually a small tree)

32. 601 Capitol After Dark peppermint willow (Agonis flexuosa ‘Jervis Bay Afterdark’), SW Australian cultivar (2 trees in sidewalk pockets; often less vigorous than the green-leafed species; compare with a green-leafed specimen of this species at #7 on this walk)

This tour ends here, across the street from its start at the main entrance to the Rec Ctr.

Poppy Lane Buckeye

January 22, 2025 by Michael Sullivan

I was in Glen Park recently and decided to check out the massive California buckeye (Aesculus californica) on Poppy Lane - one of the quaint unpaved alleys in the Glen Park neighborhood. It’s looking great - I think it’s likely the largest California buckeye in the City. Check it out - Poppy Lane between Conrad and Diamond!

What a Find!

November 15, 2024 by Michael Sullivan

I love the hunt for great trees in San Francisco. Unlike many cities, where the local government determines what is planted, and entire avenues are planted with one species, San Francisco has always given residents the right to plant what they want (within reason), which over the years has contributed to a wonderful diversity of trees in the neighborhoods. You never know what you’ll find around the corner, a serendipity that contributes to my love of San Francisco streets. And the only thing better than finding an amazing tree is finding an amazing tree in a totally unexpected place.

That’s what happened in June of this year, when Richard Turner, Jason Dewees, Sairus Patel and I were chalking our 50th chalk tree on Nob HIll, a neighborhood famous for its many tiny alleys. As we were walking west on Sacramento Street, we came upon Golden Court, which is so small that it’s not even on many maps. It’s too small for cars - Golden Alley is actually a long sidewalk that leads to the addresses along the way.

We decided to check out the alley (single file!), and you can imagine our surprise to find an amazing specimen of a lacebark tree (Brachychiton discolor) near the end of the alley. This is a tree so rare in San Francisco that the four of us knew of only one other example in the entire city. This one was a large specimen in the bloom of health.

So the next time you’re at the Fairmont Hotel or Grace Cathedral, take a 3 or 4 minute stroll to Golden Court, to see San Francisco’s “city champion” lacebark tree!

red flowering gum (*Corymbia ficifolia*)

Eureka Valley West Tree Tour

August 27, 2024 by Michael Sullivan

Who would have expected that the tree geeks would be rained out on a Saturday in late August? Yet, that is exactly what happened when Mike, Sairus, and Dick chose to meet at the corner of 18th and Storrie streets, a few blocks west of Castro Street, to explore the trees in this western corner of Eureka Valley. The clouds had been threatening on Friday and into the early hours of Saturday. Almost exactly at the appointed meeting time, light rains began, and continued for over an hour—all the result of a former typhoon that bypassed Japan in favor of a modest hit to California.

With sidewalks too wet to accept chalk, the geeks decided to walk the route and photograph some of the outstanding trees to be seen on the streets and in private gardens along the way. This is a quiet neighborhood, on the far edge of the Castro District, with homes ranging from historic Victorian and Edwardian to trendy contemporary styles. Trees can be seen in abundance, as might be expected of this moderately upscale neighborhood with its well-educated population. Among the trees noted are some city champions, and some markedly uncommon trees for San Francisco.

Today’s walk begins at the unnamed community garden on the southern side of the one-block-long Storrie Street, from Market to 18th streets. Previously a leftover strip of undeveloped land with topographical challenges, it has in recent decades evolved into a delightful public park, almost all at the hands of a local, born-in-San Francisco chap who tends the garden daily. (He’s happy to chat with anyone who drops in to see the garden.) The park is notable for some giant cottonwoods (Populus sp.) and a few eucalypts and their kin from Australia.

We strolled west on 18th, passing the former Sha’ar Zahav Jewish synagogue before turning south onto 19th Street, which curves around and heads east after crossing Caselli Avenue. At Yukon Street, we noted the large Monterey pines (Pinus radiata) in Goat Hill Park on the far corner, before turning north on Yukon Street. We turned east (right) on Caselli and followed it to tiny Clover Lane, which rises to Thorp Lane. We followed Thorp east to its end at 19th, and headed east on 19th to Douglass Street. There we turned north, walking past the glorious Caselli Mansion at Douglas and Caselli. We ended our walk at 18th. Our walk was roughly a mile in length.

We may return to this neighborhood for a properly chalked walk, but, in the interim, we hope you’ll enjoy some of the photographs taken along the way.

red flowering gum (*Corymbia ficifolia*) infloresence just about to open

a petunia in an 18th Street garden - a friend saw this picture and declared it “goth” :)

Fall color on 19th Street - a maple hybrid (probably *Acer x freemani*)

a gold medallion tree (*Cassia leptophylla*) on 19th Street

a Monterey pine (*Pinus radiata*) in front of the Caselli mansion

A red flowering gum in the Castro neighborhood

Red Flowering Gums - San Francisco's Best Tree! Why have we stopped planting them?

July 17, 2024 by Michael Sullivan

Please join Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms, Mike Sullivan (author of Trees of San Francisco and webmaster of www.sftrees.com) and Richard Turner (retired editor of Pacific Horticulture) in declaring the last week of July as “red flowering gum week” in San Francisco. This amazing tree is in full bloom now - we need to start planting it again! Spread the word:

WHEREAS red flowering gum trees have stunningly beautiful red, orange, pink or white flowers every summer that outshine any other tree in San Francisco; and

WHEREAS mature red flowering gums are large trees with leaves that remain on the tree year-round, and so are excellent contributors to the fight against climate change; and

WHEREAS as natives of Western Australia, red flowering gums thrive in our cool coastal climate; and are one of the best adapted trees to San Francisco’s conditions;

WHEREAS the largest documented red flowering gum in Northern California, and the 2nd largest in the United States, is in San Francisco in San Francisco’s St. Francis Woods neighborhood in the Monterey Boulevard median near the intersection of Junipero Serra Boulevard; and

WHEREAS red flowering gums bloom from early July through September, but reach their peak bloom in late July;

WHEREAS the flowering season of red flowering gums coincides with peak tourist season in San Francisco, offering visitors Instagram-worthy brilliant floral displays;

WHEREAS, despite these many positive attributes, the City of San Francisco has virtually stopped planting red flowering gum trees;

NOW, THEREFORE, BE IT RESOLVED, that the many fans of this amazing tree declare the last week of July now and henceforth to be “Red Flowering Gum Week” in the City and County of San Francisco, dedicated to promoting the many advantages of, and sharing images and information about, San Francisco’s best tree!

in front of Mission High School in the Mission District

Monterey Boulevard in St. Francis Woods - this street is lined with red gums!

Southeast Bernal Heights Tree Tour

July 15, 2024 by Michael Sullivan

We return for a fourth walk on the slopes of Bernal Heights, this time to the southeastern corner of the neighborhood. Known for its mix of 19th, 20th, and 21st century residences, the neighborhood also offers dramatic views to the south and east, and a lively shopping district along Cortland Avenue. Despite the notoriously narrow streets, trees are common and diverse, including two that are “city champions” - the largest of their kind in the City.

Today’s walk begins at the northwest corner of Nevada Street and Cortland Avenue, and heads north (uphill) on Nevada to Powhattan Avenue, then east on Powhattan one block to Nebraska Street. Head south (downhill) on Nebraska to Cortland, and then east on Cortland for about half a block. The walk continues on the south side of Cortland on Bronte Street. (Be careful crossing Cortland as there is no crosswalk at this point; it may be safer to go further east and use the crosswalk at Bradford Street.) Head south (now, uphill) on Bronte to Jarboe Avenue, then west on Jarboe to Putnam Street, and north (downhill) on Putnam to Cortland. The walk ends one block west at Cortland and Nevada. This walk is about 1 ½ miles in length, with some moderately steep slopes.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 23. White arrows on the pavement provide directions whenever a turn is needed.

Nevada Street, Cortland to Powhattan, west side

1. 170 Nevada Sweetgum (Liquidambar styraciflua), E USA to Mexico & Central America

2. 147 Nevada Mock-orange or tobira (Pittosporum tobira), Japan & Korea (tree is across the street; clusters of intensely fragrant, white flowers; typically grown as a large shrub, this one is a city champion, largest in SF)

3. 134 Nevada Bronze loquat (Rhaphiolepis deflexa, syn. Eriobotrya deflexa), S China and Vietnam

4. 114 Nevada Santa Cruz Island ironwood (Lyonothamnus floribundus ssp. aspleniifolius), CA’s Channel Islands, except Catalina Island (this one is flowering heavily; others can be seen along Cesar Chavez Street, just north of Bernal Heights)

5. 104 Nevada Purple (or blue) potato bush (Lycianthes rantonnetii), Paraguay (typically a large shrub, this one has been trained into a multi-trunked, tree-like form; flowers are produced all year)

Powhattan Avenue, Nevada to Nebraska, south side

6. 900 Powhattan Champak (Magnolia champaca) S & SE Asia (small, magnolia-like flowers, appearing in summer, are intensely fragrant; these three trees have been pruned in an unfortunate manner)

7. 2 Nebraska Cabbage tree (Cussonia spicata), S Africa (tree is on Powhattan; a curious, uncommonly grown tree in SF; the palmately lobed leaves are distinctive; note the thick stems developing flower buds on the right-most trunk)

**Note this richly planted corner garden at Powhattan and Nebraska, created and maintained by the talented Elliot Goliger of Artisans Designs.

Nebraska Street, Powhattan to Cortland, west side

8. 2 Nebraska Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia (the big show of blue purple flowers is just beginning, now that the leaves have fallen; these heat loving trees are becoming more common in SF, especially in warmer areas of the city—all thanks to climate change)

9. 2 Nebraska Hercules tree aloe (Aloidendron ‘Hercules’), hybrid of two S African species

10. 38 Nebraska Mediterranean fan palm (Chamaerops humilis), Mediterranean Basin: Portugal & Morocco to Tunisia & Italy (this is a young specimen that will grow into a low multi-trunked tree; northernmost natural range of any palm in the world)

11. 48 Nebraska Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (first introduced in San Francisco; these two specimens are among the largest in the city)

12. 26 Nebraska Hybrid crape myrtle (Lagerstroemia hybrid.), Asia (watch for the flowers that will be opening soon, and for the glorious fall foliage color)

Cortland Avenue, Nebraska to Bradford, north side

13. 1410 Cortland Canary Island date palm (Phoenix canariensis), Canary Islands, Spain (a “grove” of three trees in this large yard; this is the species seen in the median of Upper Market Street and along the Embarcadero)

***Please cross Cortland carefully, perhaps using the crosswalk at Bradford Street, half a block to the east. Bronte Street is midway between Nebraska and Bradford, on the south side of Cortland.***

Bronte Street, Cortland to Jarboe, west side

14. 16 Bronte African fern pine (Afrocarpus falcatus, formerly A. gracilior), E & S Africa (this is the largest specimen in the city: a city champion)

15. 20 Bronte Queen palm (Syagrus romanzoffiana), S Brazil (one tall mature specimen and one much younger specimen)

16. 36 Bronte Elegant water gum (Tristaniopsis laurina ‘Elegant’), E Australia (this selection of the water gum has longer, glossier leaves than the species)

17. 62 Bronte Sweetshade tree (Hymenosporum flavum), E Australia (the fragrant yellow flowers appear in late spring through much of the summer; this tree often grows tall and narrow at first, eventually broadening its canopy)

Putnam Street, Jarboe to Cortland, east side

Giant bird-of-paradise (*Strelitzia nicolai*)

18. 77 Putnam Giant bird-of-paradise (Strelitzia reginae), E South Africa (note the huge, blue and white flowers on this young tree, compared to the much smaller, bright orange and blue flowers on the nearby common bird-of-paradise, which grows as a shrub)

19. 75 Putnam Washington thorn (Crataegus phaenopyrum) E USA (note the white flowers that will become colorful fruits in late fall, but beware of the long thorns on the branches)

20. 59 Putnam Mayten (Maytenus boaria), Chile (five trees with gracefully pendant branches, resembling those of weeping willows)

21. 42 Putnam Purple-leaf plum (Prunus cerasifera), Eurasia (two trees across the street) pink flowers usually appear by February; formerly SF’s most planted street tree; often seen without leaves through fall and winter)

22. 14 Putnam Glossy privet (Ligustrum lucidum), S China

Cortland Avenue, Putnam to Nevada, south side

23. 1302 Cortland Purple hopseed tree (Dodonaea viscosa ‘Purpurea’), native throughout tropical and subtropical parts of the world

Today’s walk ends here, kitty-corner from its beginning.

Our regular commercial: This walking tour was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; Richard Turner, retired editor of Pacific Horticulture magazine and Sairus Patel, soon to be author of Trees of Stanford. You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. Richard edited another great book on San Francisco trees: Elizabeth McClintock’s Trees of Golden Gate Park. If you’re a tree enthusiast, buy all four of these books!

Grace Cathedral, decked out for Pride Month

Nob Hill Tree Tour (6-1-24)

June 01, 2024 by Michael Sullivan

For our 50th (!) chalk tree tour, we chose Nob Hill - one of the most iconic of the city’s many historic neighborhoods. Crowned by the magnificent 20th century Gothic-style Grace Cathedral, the hilltop is the home of the city’s finest hotels, the only Gilded Age mansion to survive the 1906 earthquake and fire (built by James Flood), and beautiful Huntington Park—a formal oasis in the heart of the city. As we chalked this tour on the first day of Pride Month, colorful flags and banners waved from all the hotels, along with rainbow-painted steps from Taylor Street up to the Cathedral’s main entrance, all in honor of the city’s diverse and inclusive culture. With the exception of the Flood mansion, all of the buildings in this predominantly residential neighborhood were built after the 1906 earthquake; the diversity of architectural styles is captivating. For such a dense neighborhood, trees are surprisingly plentiful and unexpectedly diverse.

Today’s walk is a simple one. It begins at the Interfaith Memorial Labyrinth at the top and to the side of the steps at Grace Cathedral, which is on Taylor Street between California and Sacramento streets. The Labyrinth is ringed with some particularly fine purple leaf plums (a Prunus cerasifera cultivar). From the Labyrinth, follow the walkway north towards the Canary Island date palm, which is tree #1. Once down at street level, head west on Sacramento past Jones Street to Golden Court. After exploring this fascinating pedestrian lane, continue west on Sacramento past Leavenworth Street to Kimball Place, another intriguing lane. Then, return to Leavenworth and head north to Clay Street, east on Clay to Taylor, and back south on Taylor to the Cathedral. Cross Sacramento and Taylor streets to enter Huntington Park for a delightful spot to sit and rest your feet. This walk is almost a mile and a half in length.

Grace Cathedral’s labyrinth, surrounded by purple leaf plum trees (*Prunus cerasifera*)

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 24. White arrows on the pavement provide directions whenever a turn is needed.

Left to right: Jason Dewees, Mike Sullivan, Sairus Patel and Richard Turner (in front of a king palm - (Archontophoenix cunninghamiana)

The street addresses provided below will help when the chalk has faded. Most of the trees on this walk are planted in sidewalk pockets; a few are planted within the front or rear gardens of homes along the route. And a few are found in the quaint and curious dead-end lanes that are found in this neighborhood—reminiscent of the mythical Barbary Lane in Armistead Maupin’s Tales of the City.

2. 1230 Sacramento Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (tree is across the street; first introduced in San Francisco)

**Note the beautifully shaped bougainvillea on the ornate building next door to 1230.**

3. N side of Cathedral Italian buckthorn (Rhamnus alaternus), Mediterranean Basin (this is typically a shrub but has been trained into a tree form here)

**Note the well-planted vertical garden, filled with a variety of ferns, on the north wall of the Cathedral School for Boys, just east of Jones.**

Sacramento Street, Jones to Golden Court, south side

4. 1155 Jones Indian laurel fig (Ficus microcarpa ‘Nitida’), southern Asia to N Australia (the entire block is planted with this tree, and other blocks as well; formerly one of SF’s most planted trees)

5. 1329 Sacramento Allspice magnolia (Magnolia x foggii), hybrid of two Asian species, M. figo and M. doltsopa (tree is growing in the narrow and dark gap between the buildings; despite the deep shade, it is flowering heavily; enjoy the intense fragrance of the white blossoms; it is likely a city champion)

a dragon guarding the trees on Golden Court

Golden Court, south of Sacramento

6. 10 Golden Lacebark tree (Brachychiton discolor), Eastern Australia (this rarely planted tree is 25 years old, and is a “City Champion” - the biggest of its species in San Francisco. We know of only one other lacebark tree in SF, so this was an unexpected and delightful surprise!

7. 8 Golden Iochroma fuchsioides, Andes of Ecuador and Columbia (typically known as a long-flowering shrub in SF, it will grow to tree-like dimensions in the Andes; it has no common name)

8. 9 Golden Lilly pilly tree (Syzygium smithii, previously known as Acmena smithii), E Australia (note the clusters of tiny white flowers and pale lavender fruits)

Karaka (*Corynocarpus laevigatus*) leaves

9. Golden Karaka (Corynocarpus laevigatus), New Zealand

10. Golden Douglas-fir (Pseudotsuga menziesii), West Coast & Rocky Mountains (tall conifer with needle-like leaves, almost hidden by all the shrubs; a CA native tree!)

**Continue west on Sacramento, past Leavenworth, to Kimball Place**

Kimball Place, south of Sacramento

11. South end of Kimball Cabbage tree or tī kōuka in Māori (Cordyline australis), New Zealand

Coast redwood (Sequoia sempervirens), Big Sur to SW Oregon; CA coastal native (2 trees rising out of this crowded space; this species is the tallest tree in the world)

Japanese maple (Acer palmatum), Japan, China, Korea

**Return to Leavenworth and head north**

Leavenworth Street, Sacramento to Clay, east side

12. 1202 Leavenworth Red-flowering gum (Corymbia ficifolia), SW Australia (produces bright red, orange, or pink flowers in summer; among the best and showiest of trees in SF’s urban forest; we cannot understand why the city is no longer planting this amazing tree!)

Mike, looking incredulous that the Public Works Department has banned the planting of SF’s most amazing tree!

13. 1228 Leavenworth Brisbane box (Lophostemon confertus), E Australia

14. 1250 Leavenworth River wattle (Acacia cognata), SE Australia

15. 120 Leavenworth King palm (Archontophoenix cunninghamiana), E Australia

One-sided bottlebrush (Calothamnus quadrifidus), Western Australia (this is usually a large shrub, not a tree; rarely seen in SF gardens)

Clay Street, Leavenworth to Jones, south side

16. 1385 Clay Olive (Olea europaea), Mediterranean Basin (4 young trees)

17. 1357 Clay Ginkgo (Ginkgo biloba), China (last of an ancient lineage of gymnosperms) Note that there is another ginkgo just past this one, and this 2nd ginkgo is a female, bearing malodorous fruits.

18. 1340 Clay Chitalpa (xChitalpa tashkentensis), hybrid of two native USA species, one from the SW deserts and one from the Midwest (3 small trees are in sidewalk pockets across the street; this hybrid species typically languishes in SF’s cool summer climate; reflected heat off the building appears to benefit these specimens; watch for soft lavender pink flowers later in the summer)

19. 1301 Clay New Zealand Christmas tree, pōhutukawa in Māori (Metrosideros excelsa), New Zealand (several trees on both sides of Clay and along Jones; this tree flowers most reliably in the summer months, which would be Christmas time in NZ, south of the equator)

Clay Street, Jones to Taylor, south side

20a. 1250 Jones Elegant water gum (Tristaniopsis laurina ‘Elegant’), E Australia (tree is on Clay; this selection of the water gum has longer, glossier leaves than the species)

20b. 1216 Clay Avocado tree (Persea americana), Mexico & Central America (a small tree is poking out of the entry courtyard of the building across the street)

21. 1217 Clay Pygmy date palm (Phoenix roebelenii), southern China, Laos, Vietnam

22. 1217 Coppertone Indian hawthorn (Rhaphiolepis ‘Coppertone’), hybrid of two E Asian species, Eriobotrya deflexa and Rhaphiolepis indica (3 round-headed trees across the street; new spring growth is coppery in color)

Taylor Street, Clay to Sacramento, west side

23. 1137 Taylor Chinese elm (Ulmus parvifolia), China, Korea, Japan, and Vietnam

Huntington Park, all sides

24. Huntington Park block London plane tree (Platanus x hispanica, formerly Platanus acerifolia), hybrid of E USA species and European species (this tree surrounds the park, and there are many more throughout the neighborhood, almost all of them pollarded as this one is; this hybrid species is among the most commonly planted tree in cities around the world).

25. Huntington Park, south side Ray Hartman ceanothus (Ceanothus ‘Ray Hartman’), hybrid of CA native species (clusters of soft blue flowers in winter/early spring). This one is one of the largest we know of in San Francisco - it may be a “City Champion”!

Today’s walk ends here. Take time to enjoy the quiet beauty of Huntington Park, where there are a variety of other trees, including a number of blackwood acacias (Acacia melanoxylon) and a stunning specimen of Ray Hartman ceanothus (Ceanothus ‘Ray Hartman’) next to Mrs James Flood’s fountain in the southeast corner of the park.

Bunya bunya in West Portal Removed by Owner - Another one of SF's Best Trees is Gone

March 26, 2024 by Michael Sullivan

Another very sad story for San Francisco tree lovers - the majestic bunya bunya tree (Araucaria bidwillii) at 201 Vicente Street in the West Portal neighborhood, has been removed by the owner. Nothing left but a stump. I don’t have the details as to why, but I do know it was done without a permit - which is a no no, since the tree was a “significant tree” that was close enough to the sidewalk to require a City permit for removal. The Public Works Department is aware of the violation and will be dealing with the owner.

This is the second of San Francisco’s “top 10” trees to be lost within the last year - the amazing California buckeye at Willard Street North and McAllister died of unknown causes last winter, and now this. I previously ranked the California buckeye as my #2 in the City and this bunya bunya was #4. Both trees are highlighted in my Trees of San Francisco book. So sad to lose these two landmarks!

Trees of Angel Island (2-24-24)

February 26, 2024 by Michael Sullivan

I did a bike trip to Angel Island today, not thinking I would see a lot of tree diversity. As expected, the island is full of coast live oaks, toyon and the occasional California buckeye and California bay. But what I didn’t expect was to find some unusual specimen trees near the Angel Island Immigration Museum.

To get to the immigration museum, you head downhill from the Perimeter Road at a point on the northeast part of the island. On the walk down, on your left you’ll see a couple of stately spotted gums (Corymbia maculata).

Continue down the road to the open area below the museum, and to your far left is a large bunya bunya tree tree (Araucaria bidwillii), native to Australia. Bunya bunyas are rare in San Francisco, and one of our best was just cut down in West Portal at Vicente and Wawona, so this was a welcome sight.

bunya bunya tree (*Araucaria bidwillii*)

At the other end of the clearing near the museum is a close relative of the bunya bunya - a Norfolk Island pine (Araucaria heterophylla), also large and mature. It wouldn’t surprise me if they were planted at the same time.

And in between the two Araucaria, facing the water, two Canary Island date palms (Phoenix canariensis).

Angel Island used to be full of blue gum eucalyptus trees (Eucalyptus globulus), but 80 acres of eucalyptus were removed in the 1990s - among other things, they were thought to be a fire hazard that created risk for the nearby historic buildings. However, there are still beautiful specimens of this tree to be found around the island.

blue gum eucalyptus (*Eucalyptus globulus*)

And lastly, the most common tree on the island - coast live oak (Quercus agrifolia).

Trees of Mexico City (1-25-24)

February 13, 2024 by Michael Sullivan

I visited Mexico City with my family in late January 2024 - we stayed in the Roma Norte neighborhood, and didn’t stray very far from there, so this blog may not be representative of the entire city’s trees.

It was my first time in Mexico City. I had heard that the city was very leafy, and I found that to be accurate. In fact, at least in the Roma Norte neighborhood, the street trees are so dense that it’s not easy to get an Instagram-worthy photo of an individual tree! This link from Google maps of a street not far from our hotel will give you a sense of this part of Mexico CIty.

We visited one of the city’s botanical gardens (Jardin Botanico del Bosque de Chapultepec), but I found it underwhelming. The cactus and agave collections were attractive, but the park is relatively small (13 acres), and very few tree specimens were labeled.

The three species that dominated the streets of our neighborhood were shamel ash (Fraxinus uhdei), glossy privet (Ligustrum lucidum) and American sweetgum (Liquidambar styraciflua). Two of the three are native to Mexico - shamel ash is native from west-central Mexico to Costa Rica, and sweetgum is found in disjointed areas from central Mexico to Nicaragua.

The ash trees were the most abundant of all, which saddened me a bit to think that the emerald ash borer is marching across the continent, killing every ash it encounters, and eventually I suspect will make it to Mexico City.

shamel ash (*Fraxinus uhdei) - closeup of leaves and samaras (fruits)*

glossy privet (*Ligustrum lucidum*) - closeup

American sweetgum (*Liquidambar styraciflua*) - closeup of leaves

Another tree that was very common on city streets was weeping fig (Ficus benjamina). It’s very rare as a street tree in my native San Francisco, but I saw it everywhere in Mexico City.

weeping fig (*Ficus benjamina*) - closeup

Occasionally I ran across orchid trees (Bauhinia purpurea) in bloom as street trees.

Not a tree, but another plant I saw everywhere in our neighorhood was split leaf philodendron (Thaumatophyllum bipinnatifidum).

When we ventured out of Roma Norte into other neighborhoods, the canopy thinned out a bit (and I also started to see some more unusual tree species. Below is a Cook pine that we encountered in the Condesa neighborhhood, not far from the city’s botanical garden. This tree always leans towards the equator (a discovery by botanist Matt Ritter in 2017), and this one was duly leaning south!

Cook pine (*Araucaria columnaris*) on Calle Juan de la Barrera near the corner of Avenida Mazatlan in the Condesa neighborhood

We visited Casa Gilardi, a home designed by minimalist architect Luis Barragan-designed - the family that has owned it since it was built it gives private tours. It’s in the San Miguel Chapultepec neighborhood, and if you’re into architecture or home design, I really recommend it. Inside the open air courtyard of the home is a large jacaranda (Jacaranda mimosifolia), a tree native to Argentina and Bolivia - but very popular in Mexico City.

jacaranda (*Jacaranda mimosifolia*) in the courtyard at Casa Gilardi

A couple of days later I saw what I think it the largest jacaranda I’ve ever seen - the address is 208 Jalapa in the Roma Norte neighborhood.

a huge jacaranda (*Jacaranda mimosifolia*) at 208 Jalapa in Roma Norte

At 7,350 feet in altitude, Mexico City isn’t tropical, but since it rarely has freezing temperatures, there are lots of palm trees that do well here. Canary Island date palms (Phoenix canariensis) were pretty common.

And not far from our hotel (at the intersection of Calle Jalapa and Calle Puebla in Roma Norte), we found a corner full of bismarck palms (Bismarckia nobilis), a tree native to Madagascar.

Compared to my native San Francisco, there were relatively few eucalyptus trees. We did see a beautiful eucalyptus relative - a spotted gym (Corymbia maculata) on Avenida Insurgentes Sur near Avenida Alvaro Obregon in Roma Norte.

spotted gym (Corymbia maculata) - Avenida Insurgentes Sur

Bailey's Acacia - first sign of a San Francisco Spring!

February 09, 2024 by Michael Sullivan

It’s a little late this year - normally this tree blooms in January in San Francisco. Bailey’s acacia (Acacia baileyana) is a tree from eastern Australia that blooms with striking yellow flowers. It’s the first of our trees to bloom - next will be the plum trees (later in February), then the cherries (March), and even later (April/May) the hawthorns.

As you can see from the partially hidden street sign, this tree is at the corner of 17th and Shrader Streets in the Cole Valley neighborhood.

And it has one more claim to fame - this tree was the one photographed by author and botany professor Matt Ritter for his (fantastic) book “A Californian’s Guide to the Trees Among Us”.

Fairmount Hill Tree Tour (2-3-24)

February 05, 2024 by Michael Sullivan

Between showers on a mostly windless day, we chose a relatively quiet neighborhood wedged between the northeastern extent of Glen Park and the southern extent of Noe Valley. It covers the lower slopes of a hill known as Fairmount, one of the many hills that make up the San Miguel Hills in this part of the city. We were pleased with the diversity of trees in this small neighborhood. But, the real draw is the variety of residential architecture, from stunning and beautifully restored Victorians to modest cottages, along with some ‘50s-‘60s apartment buildings. Laidley Street is known for its collection of radical contemporary architecture from the ‘80s and ‘90s. Take time to appreciate this diversity in residential design.

Today’s walk is a simple one. It begins on Whitney Street, at its terminus at Chenery Street. It heads north on Whitney for two blocks to Randall Street, then continues on Randall for two more blocks to Harper Street, and heads uphill on Harper to Laidley Street. From there it heads southeast-ish on Laidley to Miguel Street, downhill on Miguel to Whitney, and then north again on Whitney for a few yards. This walk is almost a mile and a half in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 34. White arrows on the pavement provide directions whenever a turn is needed.

Whitney Street, Chenery to Fairmount, east side

1. 298 Chenery Brisbane box (Lophostemon confertus), E Australia (tree is on Whitney)

2. 263 Whitney Cajeput tree (Melaleuca quinquenervia), New Caledonia, New Guinea, E Australia (3 trees, including 1 across the street; feel the distinctive spongy bark)

3. 249 Whitney Ginkgo (Ginkgo biloba), China (last of an ancient lineage; there are many ginkgos in the neighborhood, including some very young ones on Miguel)

4. 249 Whitney Chinese elm (Ulmus parvifolia), China, Korea, Japan, and Vietnam

5. 229 Whitney African fern pine (Afrocarpus falcatus, formerly A. gracilior), E & S Africa (peeking around the construction fence)

6. 219 Whitney Victorian box (Pittosporum undulatum), E Australia (common in the neighborhood; intensely fragrant white flowers cycle through the year)

7. 191 Fairmount Tree fuchsia (Fuchsia arborescens), C America (peeking over the fence on Whitney; this large shrubby fuchsia flowers all year in SF)

8. 191 Fairmount Peppermint willow (Agonis flexuosa), SW Australia (2 trees is on Whitney)

Whitney Street, Fairmount to Randall, east side

9. 159 Whitney Water gum (Tristaniopsis laurina), E Australia (this tree grows in stream-side locations in the wild, hence the common name; SF’s most commonly planted street tree)

10. 155 Whitney Mayten (Maytenus boaria), Chile

11. 119 Whitney Coast redwood (Sequoia sempervirens), Big Sur to SW Oregon; CA coastal native (this species is the tallest tree in the world)

12. 197 Randall Plume albizia (Paraserianthes lophantha, formerly Albizia lophantha), SW Australia (within the fenced garden of the property on Randall; a feathery-leafed small tree with pale yellow flowers in clusters; this species has become a weed in the western portions of Golden Gate Park and above Sutro Baths)

**Cross Whitney and continue a short distance on Randall**

Randall Street, Whitney to Sanchez, south side, then north side

13. 201 Randall Ray Hartman ceanothus (Ceanothus ‘Ray Hartman’), hybrid of CA native species (just beginning to open its blue flowers)

14. 207 Randall Indian laurel fig (Ficus microcarpa ‘Nitida’), S Asia to N Australia (formerly one of SF’s most planted trees)

**Cross Randall**

15. 200 Randall Brazilian pepper tree (Schinus terebinthifolia), Brazil, Argentina, Paraguay

16. 228 Randall Lemon bottlebrush (Callistemon citrinus), E Australia

17. 228 Randall Giant yucca (Yucca gigantea, formerly Y. elephantipes), Mexico & Central America

18. 240 Randall New Zealand Christmas tree, pōhutukawa in Māori (Metrosideros excelsa), New Zealand (this tree flowers most reliably in summer months, which would be Christmas time in NZ, south of the equator)

Randall Street, Sanchez to Harper, north side

19. 250 Randall Olive (Olea europaea), Mediterranean Basin

20. 250 Randall Meyer lemon (Citrus x meyeri), hybrid of mandarin and pomelo, both SE Asian species (in the rear yard, heavily laden with fruit)

21. 270 Randall Sweet viburnum (Viburnum odoratissimum), S, SE, and E. Asia (very uncommon in SF; usually a shrub)

** Cross Harper**

Harper Street, Randall to Laidley, west side

22. 76 Harper Bailey’s acacia (Acacia baileyana ‘Purpurea’), E Australia (this is usually among the earliest flowering trees in SF, always beginning in January with fluffy bright yellow flowers)

** Cross Laidley**

Laidley Street, Harper to Fairmount, south side

23. 128 Laidley Chinese windmill palm (Trachycarpus fortunei), China (a fine specimen)

24. 117 Laidley Texas privet (Ligustrum japonicum ‘Texanum’), E. Asia (2 trees across the street; city champions; these are usually seen as large sheared hedges)

25. 138 Laidley Cork oak (Quercus suber), Spain & Portugal (3 trees; the bark of this tree provides the cork used in wine bottles)

Cork oak (*Quercus suber*) - closeup of bark

26. 140 Laidley Black locust (Robinia pseudoacacia), E USA (this deciduous tree will have fragrant white flowers in spring)

** continue on the lower side of Laidley**

Laidley Street, Fairmount to Miguel, east side (lower side)

a beautiful Victorian home on Laidley Street

27. 237 Fairmount Willow-leaf peppermint (Eucalyptus nicholii), SE Australia (2 trees, one on each side of Laidley)

28. 233 Laidley Primrose tree (Lagunaria patersonii), Norfolk and Lord Howe islands (soft pink flowers will appear later in the year)

29. 224 Laidley Rusty-leaf fig (Ficus rubiginosa), E Australia (across the street)

30. 279 Laidley Glossy privet (Ligustrum lucidum), S China (2 trees)

Miguel Street, Laidley to Whitney, northeast side

31. 201 Miguel Tree aloe (Aloidendron barberae, formerly Aloe bainesii), S Africa to Mozambique (this specimen appears to be variegated, but the effect is due to sunscald)

32. 219 Miguel Bronze loquat (Rhaphiolepis deflexa, syn. Eriobotrya deflexa), S China and Vietnam

Whitney Street, north from Miguel, west side

33. 268 Whitney Jacaranda (Jacaranda mimosifolia), Argentina and Bolivia (watch for the big show of blue purple flowers in summer; these heat loving trees are becoming more common in SF, especially in warmer areas like the Mission District—thanks in partto climate change)

34. 260 Whitney Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (many fine specimens of this tree can be seen throughout the neighborhood; first introduced in San Francisco)

Today’s tree walk ends here, just a few yards north of its beginning at Whitney and Chenery.

Our regular commercial: This walking tour was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; Richard Turner, retired editor of Pacific Horticulture magazine and Sairus Patel, soon to be author of Trees of Stanford and Environs. You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. Richard edited another great book on San Francisco trees: Elizabeth McClintock’s Trees of Golden Gate Park. If you’re a tree enthusiast, buy all four of these books!

Pacific Heights West Tree Tour

December 10, 2023 by Michael Sullivan

On a crisp December morning, we returned to the western end of Pacific Heights, a neighborhood filled with well-kept Victorian homes, a delightful shopping district, one of the finest branch libraries in the city, and one of the few remaining single-screen movie houses (the Vogue) in town. For this tour we were happy to be joined by Josh Gevertz, Arboretum Director at Cypress Lawn Cemetery in Colma (home to some amazing trees - it was recently recognized as a Level I arboretum by Morton Arboretum’s international ArbNet program - take the virtual tree tour here).

Today’s walk begins in front of the elegant Presidio Branch Library, at 3150 Sacramento Street, and heads east on Sacramento to Baker Street, south on Baker to Pine Street, east on Pine to Lyon Street. The walk then turns south on Lyon for half a block, crosses Lyon to the east side, then heads north on Lyon to Sacramento, and finally east on Sacramento back to the Library. This walk is a little over one mile in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 25. White arrows on the pavement provide directions whenever a turn is needed.

Sacramento Street, Lyon to Baker, north side

1. 3150 Sacramento Flame tree (Brachychiton acerifolius), E Australia (a bold allee of six trees at the Presidio branch library; trees may lose their leaves just before flowering)

Baker Street, Sacramento to California, west side

2. 1819 Baker Southern magnolia (Magnolia grandiflora), SE USA (many in this block)

3. 1817 Baker Little Gem magnolia (Magnolia grandiflora ‘Little Gem’), SE USA (this selection of southern magnolia has smaller leaves, smaller flowers, and matures at a smaller size; compare with #2)

4. 1815 Baker Japanese maple (Acer palmatum), Japan, China, Korea (these trees have been pruned into a loose hedge lining the edge of the front garden)

5. 1813 Baker Brush cherry (Syzygium australe, formerly S. paniculatum), E Australia

6. 1813 Baker Irish yew (Taxus baccata ‘Fastigiata’), Irish cultivar of Eurasia & N Africa parents

7. 1811 Baker Eastern dogwood (Cornus florida ) E North America (not always the best choice for coastal California, but this one already has flower buds for next spring)

California Street, west of Baker, north and south sides

8. 3000 California Indian laurel fig (Ficus microcarpa ‘Nitida’), S Asia to N Australia (formerly one of SF’s most planted trees)

9. 3001 California Fastigiate blue Atlas cedar (Cedrus atlantica ‘Glauca Fastigiata’), Atlas Mountains of Morocco & Algeria (note the narrow upright habit of the branches)

Blue Ice yellowwood (Podocarpus elongatus ‘Monmal’), S Africa

Baker Street, California to Pine, west side

10. 1710 Baker Chinese windmill palm (Trachycarpus fortunei), China (across the street)

11. 2896 Pine Peppermint willow (Agonis flexuosa), SW Australia (tree is on the east side of Baker)

Baker Street, Pine to Bush, west side

12. 1653 Baker Modesto ash (Fraxinus velutina ‘Modesto’), SW North America (this cultivar discovered in Modesto, CA)

13. 1611 Baker London plane tree (Platanus x hispanica, formerly Platanus acerifolia), hybrid of E USA species and European species; it is among the most commonly planted trees in cities around the world; there are many in this neighborhood)

14. 1611 Baker Japanese maple (Acer palmatum), Japan, China, Korea (one of the largest in the city)

15. 1611 Baker Australian tree fern (Sphaeropteris cooperi, formerly Cyathea cooperi), SE Australia

Bush Street, Baker to Lyon, north side

16. 2810 Bush Prickly melaleuca (Melaleuca styphelioides), E Australia (note the tiny prickly leaves and spongy park; white flowers appear in summer; this is one of the biggest in town)

Lyon Street, south of Bush, west side

17. 1515 Lyon Carob (Ceratonia siliqua), E Mediterranean Basin (there are several trees in this block; seed pods can be used to make a chocolate substitute—though not recommended for true chocolate lovers)

18. 1511 Lyon Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA, native (one of the most widely planted conifers in coastal California; note the trunk is covered with English ivy, which should be removed for the health of the tree)

tree-themed art at Little School (1520 Lyon)

** cross the street carefully**

Lyon Street, south of Bush, east side

19. 1590 Lyon Victorian box (Pittosporum undulatum), E Australia (intensely fragrant white flowers cycle through the year)

Lyon Street, Bush to Pine, east side

20. 1644-46 Lyon Holm oak (Quercus ilex), Mediterranean Basin (a surprisingly uncommon tree in SF, despite its adaptability to our climate; these 2 trees are city champions)

21. 1652 Lyon Italian bay tree or Grecian laurel (Laurus nobilis), Mediterranean Basin (leaves of this tree are the bay leaves used in cooking)

Lyon Street, Pine to California, east side

22. 2296 Pine Glossy privet (Ligustrum lucidum), S China (tree is on Lyon)

23. 1740 Lyon Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (many fine specimens of this tree can be seen throughout the neighborhood; first introduced in San Francisco)

Lyon Street, California to Sacramento, east side

24. 1812 Lyon Chinese elm (Ulmus parvifolia), China, Korea, Japan, and Vietnam

Sacramento Street, Lyon to Baker, south side

25. 1832 Lyon Olive (Olea europaea), Mediterranean Basin (trees are on Sacramento)

Today’s tour ends here on Sacramento, across the street and a few doors west of the Presidio Branch Library, where it began.

Top photos of this blog's first decade!

November 05, 2023 by Michael Sullivan

I noticed recently that this blog just had a 10 year anniversary - my first post was August 30, 2013. I scrolled through the decade of posts, and found some photos that made me smile. Here are my top sftrees.com photos from the last 10 years:

Spotted gum (*Corymbia maculata*) adjacent to the Mission Pool at 19th Street between Guererro and Valencia. What a spectacular tree!

The largest Monterey cypress in the country! That’s me under the tree - In March 2021 I did a pilgrimage to see this amazing tree. It’s located at 751 Pescadero Creek Road in Pescadero - about 8 miles inland from Highway 1.

May 2020 - Jason Dewees (left), Richard Turner (right) and me on our Potrero Hill tour, next to a purple smoke tree (*Cotinus coggygria* ‘Royal Purple’). That’s a box of chalk in my hand. This was in the depths of the pandemic, so we were doing our chalk tree tours with masks.

The yellow-blooming New Zealand Christmas tree (*Metrosideros excelsa*) at 1221 Stanyan Street. My favorite individual tree in San Francisco.

A silk oak leaf on the sidewalk at ***3520 18th/Valencia*** in the Mission

A red flowering gum (*Corymbia ficifolia*) on Monterey Boulevard in St. Francisco Woods. I love this species in San Francisco more than any other. Why is the City restricting the planting of this tree??!

Garage on Grove Street in the NOPA neighborhood

A stately wine palm (*Jubaea chilensis*) at the Sunnyside Conservatory on Monterey Boulevard. It takes a LONG time for this palm species to get this tall.

And another palm - this time a Mexican fan palm (*Washingtonia robusta*) in MissionBay

The California buckeye (*Aesculus californica*) at 2694 McAllister/Willard Street - largest and probably oldest of its species in San Francisco. Sadly, this tree died over the 2022/2023 winter. Here it is in glorious bloom in June 2020.

A dawn redwood (Metasequoia glyptostroboides) in the Arnold Arboretum in Boston in August 2021 - that’s my sister Patricia under the tree for scale. The Arnold Arboretum organized the effort to bring seeds back from China after the tree was discovered in the 1940s, and this tree was planted in 1948 when the seeds arrived. This is the largest one in the arboretum, and since their trees were planted first, it may be the largest dawn redwood in the United States!

sidewalk imprint of a London plane leaf on Page Street in the Haight-Ashbury neighborhood

California buckeye (*Aesculus californica*) on Poppy Lane in Glen Park

tulip tree (*Liriodendron tulipifera*) at the corner of Kearny and Vallejo on Telegraph Hill

gold medallion tree (*Cassia leptophylla*) at 227 Cole in the NOPA neighborhood. This one is the “City Champion” - biggest of the species in San Francisco

Beautiful garage door artwork at 523 Precita near Precita Park (the owner is the artist!)

Monterey pine (*Pinus radiata*) at 214 Santa Clara Avenue. This specimen is the largest in the Western Hemisphere!

My husband and I took a trip to Sicily in April 2022 - this is a Moreton bay fig (*Ficus macrophylla v. columnaris*) in the Palermo botanical gardeny. That’s me standing behind one of the buttressing roots of the tree.

a carob tree (*Ceratonia siliqua*) in a field in Sicily

a silk floss tree (*Ceiba speciosa*) in Prospect Park in the Dogpatch neighborhood

a lonely volunteer California poppy in a San Francisco sidewalk

Row of Victorians off Page Street in the Haight Ashbury neighborhood

and just down the street on Page, Spiral aloe (*Aloe polyphylla*) at 1124 Page Street

the four of us! Jason Dewees, Sairus Patell, Mike Sullivan and Richard Turner

a lovely Guadalupe palm *(Brahea edulis)* at 333 Sussex Street in Glen Park

Precita Park/Peralta Heights Tree Tour

October 16, 2023 by Michael Sullivan

Sunny, warm, and windless—a perfect October day in San Francisco, particularly after the past four uncommonly cool months. We chose a relatively little known neighborhood for today’s walk: Peralta Heights, a hilly neighborhood on the northeastern slope of Bernal Heights. This is a fairly warm pocket of the city, with quirky architecture and a surprisingly diverse array of trees to be enjoyed.

Today’s walk begins in front of the Precita Park Cafe & Grill, at Alabama Street and Precita Avenue, and heads east on Precita to Florida Street, then crosses Precita and returns to Alabama. It then heads south on Alabama to Mullen Street, east (and slightly uphill) on Mullen all the way to Montcalm Street, then west on Montcalm to Alabama, and finally north on Alabama back to Precita. This walk is a little under one and a half miles in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 43. White arrows on the pavement provide directions whenever a turn is needed.

Beautiful garage door artwork at 523 Precita (the owner is the artist!)

Precita Avenue, Alabama to Florida, south side

1. 508 Precita Saratoga laurel (Laurus ‘Saratoga’), hybrid of Mediterranean and Atlantic species (selected form introduced by Saratoga Horticultural Foundation)

2. 548 Precita Trident maple (Acer buergerianum), E China, Taiwan, Japan (note the heavy production of the winged seeds, called samaras; likely due to the exceptional rainfall of the past winter)

3. 552 Precita Canary Island date palm (Phoenix canariensis), Canary Islands, Spain (a young specimen, barely showing a trunk but providing plenty of shade; this is the species seen on Market Street and along the Embarcadero)

Precita Avenue, Florida to Alabama, north side

4. 523 Precita Silver dollar gum (Eucalyptus polyanthemos), E Australia (the leaves on young shoots have the approximate size and shape of a silver dollar)

5. 523 Precita Sweet michelia (Magnolia doltsopa), Himalayas (the brown buds in the leaf axils will become large white, intensely fragrant flowers in winter)

Precita Avenue at Alabama Street, center island

6. Precita & Alabama Mexican fan palm (Washingtonia robusta), S Baja & Sonora, Mexico (3 tall trees in the triangle where Precita and Alabama meet)

Alabama Street, south of Precita, west side

7. 1600 Alabama Cajeput tree (Melaleuca quinquenervia), E Australia to Papua New Guinea (3 trees; feel the distinctive spongy bark)

Alabama Street, Precita to Mullen, east side

8. 1619 Alabama Australian willow or wilga (Geijera parviflora), inland E Australia (this tree generally prefers the warmth of the eastern parts of the city)

9. 1625 Alabama Washington thorn (Crataegus phaenopyrum) E USA (note the colorful fruits, but beware of the long thorns on the branches)

10. 1627 Alabama Ginkgo (Ginkgo biloba), China (a fine multi-trunked specimen, one of many in the neighborhood; last of an ancient lineage)

11. 1639 Alabama Sweetgum (Liquidambar styraciflua), E USA to Mexico & Central America

Closeup of bark - Evergreen pear (*Pyrus kawakamii*)

12. 1653 Alabama Evergreen pear (Pyrus kawakamii), Taiwan (only in cold winters does this species lose its leaves in San Francisco)

Mullen Avenue, Alabama to Peralta, south side

13. 40 Mullen Peruvian pepper tree (Schinus molle), Peru & Chile

14. 70 Mullen Karo (Pittosporum crassifolium), New Zealand

Mullen Avenue, Peralta to Franconia, north side

15. 131 Mullen Monterey cypress (Hesperocyparis macrocarpa), Carmel, CA (across the street, along the sloping walkway; a California native, and one of the three most commonly planted trees in SF’s parks)

Mullen Avenue, Franconia to Montcalm, north side

16. 201 Mullen Valley oak (Quercus lobata), California (at the top of the Franconia Steps; very rare in SF)

17. 211 Mullen Pearl acacia (Acacia podalyriifolia), E Australia (the first flowers of the season are opening)

18. 239 Mullen Gold medallion tree (Cassia leptophylla), SE Brazil (in full bloom)

***The next four trees are survivors from the exceptional garden of Tom and Jeong, who moved away some years ago***

19. 285 Mullen Chinese windmill palm (Trachycarpus fortunei), China (2 trees)

20. 285 Mullen Beaked yucca (Yucca rostrata), Mexico and Texas

21. 285 Mullen Tree aloe (Aloidendron barberae, formerly Aloe bainesii), S Africa to Mozambique (this may be the tallest specimen in the city)

22. 285 Mullen Mountain cabbage tree (Cussonia paniculata), E South Africa (note that the right branch has begun to drop its leaves as the curious flowers develop)

Montcalm Street, Mullen to Franconia, north side

23. 100 Mullen Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (2 trees on Montcalm; this hybrid was first introduced in San Francisco and named for the Marina District)

24. 110 Montcalm Coast redwood (Sequoia sempervirens), Big Sur to SW Oregon; CA coastal native (this species is the tallest tree in the world)

24b. 128 Montcalm Elegant water gum (Tristaniopsis laurina ‘Elegant’), E Australia (this selection of the water gum has longer, glossier leaves than the species)

25.150 Montcalm Avocado tree (Persea americana), Mexico & Central America

A guerrilla carving of a stairway fence post!

***The next seven trees are survivors from the exceptional garden of Geoff and Chip, who moved away many years ago***

26. 198 Montcalm Trumpet bush (Tecoma hybrid), hybrid of tropical American species (this is actually a large shrub, but here it towers over the sidewalk)

27. 198 Montcalm Pindo palm (Butia odorata), SE Brazil & Uruguay

28. 198 Montcalm Guadalupe palm (Brahea edulis), Guadalupe Island, Mexico (this palm is perfectly adapted to SF; it has been used in the median of Cesar Chavez Street in the Mission District)

29. 198 Montcalm Australian fan palm (Livistona australis), E Australia

30. 198 Montcalm King palm (Archontophoenix cunninghamiana), E Australia

31. 198 Montcalm Norfolk Island palm (Rhopalostylis baueri), Norfolk Island & Kermadec Islands

32. 198 Montcalm Desert fan palm (Washingtonia filifera), S California, Arizona, and N Baja (generally uncommon in SF, as it prefers more summer heat; compare the fatter trunk and the greater number of thread-like filaments on the leaves of this species vs the tall Mexican fan palms seen in the rest of this block of Franconia)

Montcalm Street, Franconia to Peralta, north side

33. 206 Montcalm Italian stone pine (Pinus pinea), Mediterranean Basin (the source of pine nuts/pignoli)

34. 205 Montcalm Nikau or shaving brush palm (Rhopalostylis sapida), New Zealand (the young tree is across the street)

35. 259 Peralta Flannel bush (Fremontodendron californicum), California, Arizona, N Baja (tree is on Montcalm at the corner of the park; beware of the fine hairs on the leaves; they can be irritating)

36. 259 Peralta Hollywood juniper (Juniperus chinensis ‘Torulosa’ or ‘Kaizuka’), E Asia (tree is on Montcalm at the corner of the park, behind the flannel bush)

37. 229 Montcalm California buckeye (Aesculus californica ), California & Oregon; a San Francisco native tree! (tree is across the street, to the left of the continuation of Peralta Avenue

Montcalm Street, Peralta to Alabama, north side

38. 300 Montcalm Blue Atlas cedar (Cedrus atlantica ‘Glauca’), Atlas Mountains of Morocco & Algeria (2 trees)

39. 306 Montcalm Japanese maple (Acer palmatum), Korea and Japan (2 trees)

40. 308 Montcalm Bronze loquat (Rhaphiolepis deflexa, syn. Eriobotrya deflexa), S China and Vietnam

41. 329 Montcalm Lemonwood or tarata (Pittosporum eugenioides), New Zealand (tree is across the street)

Ginkgo (*Ginkgo biloba*) - female fruits

42. 366 Montcalm Ginkgo (Ginkgo biloba), China (there are many ginkgos in the neighborhood; however, this one is a female, hence the foul-smelling fruit in autumn)

Alabama Street, Montcalm to Mullen, east side

43. 1669 Alabama European weeping birch (Betula pendula), Eurasia & N Africa (not usually well-adapted to SF, but this specimen is outstanding)

This tree walk ends here. To return to its beginning, continue north for one more block to the Precita Park Cafe & Grill.

Trees of Copenhagen

August 10, 2023 by Michael Sullivan

I visited Copenhagen in July 2023, and found some remarkable trees in the four days that I was there, all in the central part of the city. Some were in Copenhagen’s very nice botanical garden, some in the King’s Garden, one in the city’s best art museum (!), and one in a pot just outside the home where we stayed. See below!

Lavalle hawthorns (Crataegus X lavallei) adjacent to the Little Mermaid

Perhaps the most famous tourist attraction in Copenhagen is the “Little Mermaid”. Some of our friends told us not to bother, but we were strolling along the water on our first day in the City, and ran across it. Just adjacent to the Little Mermaid was a small grove of Lavalle hawthorns (Crataegus X lavallei).

The King’s Garden (also known as Rosenborg Garden) in central Copenhagen is the oldest and most visited park in central Copenhagen - it was established in the early 17th century as the private garden of King Christian IV's Rosenborg Castle, which is adjacent. It’s full of stately mature trees that are happy in northern Europe.

White willow (*Salix alba*) in the King’s Garden

Common lime or European lime (*Tilia X Europaea*) in the King’s Garden

I don’t normally expect to find landmark trees in art museums, but just inside the entrance to the Glyptoteket (Copenhagen’s best art museum) was this nice example specimen of a Canary Island date palm (Phoenix canariensis).

Canary Island date palm (*Phoenix canariensis*) in the Glyptoteket

And Copenhagen has a lovely botanical garden in center city. It was raining off and on the day I visited, but in between the showers I found some trees worth noting. Just inside the gate on the left was an empress tree (Pawlonia tomentosa) - easily identifiable by the huge leaves and distinctive seeds.

empress tree - closeup of leaves and fruits

If you stay to the left after entering the garden, eventually you will reach this sweet chestnut tree (Castanea sativa). I didn’t find man of these in Scandinavia on our trip, so it caught my eye.

sweet chestnut (closeup - leaves and fruits)

I think the most impressive grouping of trees were on a small hill near the center of the garden. Side by side were two trees that are actually fairly close relatives - a dawn redwood (Metasequoia glyptostroboides) right next to a coast redwood (Sequoia sempervirens). The coast redwood is the tallest tree in the world, and the dawn redwood was thought to have been extinct (known only from fossil records) until a specimen was discovered in central China in 1941.

A dawn redwood (*Metasequoia glyptostroboides*) on the left, right next to a coast redwood (*Sequoia sempervirens*) on the right

And just behind these two, another close relative of both - a giant sequoia (Sequoiadendron giganteum), native to the Sierra Nevada Mountains of Central California. This is the tree that is the most massive tree in the world, and it was in the bloom of health here in Copenhagen!

We stayed very close to “Churchillparken” (Churchill Park) in Copenhagen, and as I meandered there one day, I ran across this spectacular specimen of sycamore maple (Acer pseudoplatanus). We don’t see this tree much in my hometown of San Francisco, so it was a treat to find it (and many others nearby).

sycamore maple (*Acer pseudoplatanus*) in Churchillparken (Churchill park)

And not too far away, next to one of the many canals, a weeping willow (Salix babylonica).

weeping willow (*Salix babylonica*) in Churchill Park

And finally, I think it’s a little cold for this tree in Copenhagen, but just outside the home where we were staying was this baby monkey puzzle tree (Araucaria araucana). I’m sure it will be brought inside for the winter!

monkey puzzle tree (*Araucaria araucana*)

Reunited with an old friend - American beech

July 28, 2023 by Michael Sullivan

I grew up in a maple/beech climax forest in Herkimer County, New York. I could walk out my door and follow trails leading into the forest behind our home, and within minutes I’d be deep in a dark forest of American beech trees (Fagus americana). I absolutely loved these trees - stately, with beautifully smooth grey bark, and beautiful leaves - one nature writer wrote that “an unearthly pale pure green clothes the tree in a misty nimbus of light”.

Sadly, since I left the northeast, American beech trees have been suffering from beech bark disease, disease that causes mortality and defects in the trees. I tried to find my old friends, the gigantic smooth-barked giants of my childhood, but they were all dead - I saw occasional stumps, but nothing else.

But it wasn’t all sad - I remember clearly planting a beech sapling in the 1970s in a clearing just behind our home in Poland, New York. A few weeks ago I visited that exact spot to see if it was still there, and was so happy to see it thriving. That’s me with my tree in the photo above.

One reason I was happy to find my old friend is that I hadn’t seen one of his kind in a long time. You’ll never see an American beech in the Bay Area - the tree can’t handle the compacted soils of our cities, and I suspect 8 months without rainfall is also tough for a tree that’s used to the rainy East Coast. All of the beech trees in urban and suburban California are European beech (Fagus sylvatica).

Valencia - Guerrero Tree Tour

July 10, 2023 by Michael Sullivan

Yes, another chilly, overcast, and ridiculously windy summer day in San Francisco… We chose to focus today’s walk on a portion of the Mission District that merges with the Liberty Hill Historic District, between 19th and 23rd streets and between Valencia and Guerrero streets. We have touched on this neighborhood before, but this tour focused on the blocks between Valencia and Guerrero. In addition to some striking mature trees and magnificent Victorian-era homes in the Liberty Hill area, there are plenty of appealing dining and drinking establishments to enjoy along Valencia Street.

Today’s walk begins in front of the Mission Pool and Playground, on 19th Street at Linda Street. Head east on 19th to Valencia Street, then south on Valencia to 20th Street. Head west on 20th to Guerrero, then south on Guerrero to Liberty Street, and east on Liberty back to Valencia. Continue south on Valencia to 21st Street, west on 21st to Guerrero, south again on Guerrero to Hill Street, east on Hill to Valencia, south on Valencia to 22nd, and east on 22nd to Guerrero again. At Guerrero, cross 22nd and head back east on 22nd to San Jose Avenue, then south on San Jose to Alvarado Street, west briefly on Alvarado and then back to San Jose. Head south on San Jose to the SW corner of 23rd Street. The tour ends here; unlike most of our tours, this is a one-way route, not a loop. Go back to Valencia to return to the start of the tour. This one-way walk is under two miles in length.

Numbered trees are labeled with common and scientific names and country of origin, all written in white chalk on the sidewalk; accompanying numbers, in blue, run from 1 to 45. White arrows on the pavement provide directions whenever a turn is needed.

19th Street, Linda to Valencia, north side

1. 19th at Linda We decided to start our tour with one of our favorite trees in San Francisco. This spotted gum (Corymbia maculata) is the tall tree with almost white bark, against the building). It’s native to eastern Australia - and this tree made it onto my “top 10” list of all of San Francisco’s trees!

2. 3543 - 19th English walnut (Juglans regia), Balkans, Iran, and India to Central China (tree is in the rear yard of the blue house; the best walnut for eating)

3. 3519 - 19th Weeping bottlebrush (Callistemon viminalis), E Australia (an uncommonly tall specimen)

4. 3519 - 19th Chinese pistache (Pistacia chinensis), W & C China (not commonly planted in SF, since it prefers greater summer heat to develop its spectacular fall foliage colors)

5. 3505 - 19th Chinaberry (Melia azedarach), S Asia to Australia (2 trees, the only ones in SF; a weed elsewhere; one of the few trees in the mahogany family found in SF)

Valencia Street, 19th to 20th, west side

6. 850 Valencia Shiny xylosma (Xylosma congestum), China (3 trees along the northern fence line within the park; rare in SF; often grown as a large shrub)

7. 850 Valencia Freeman maple (Acer x freemanii), hybrid of Acer rubrum & Acer saccharinum, both from E North America (3 trees in the sidewalk in front of the Mission Playground)

20th Street, Valencia to Guerrero, south side

8. 3635 - 20th Norfolk Island pine (Araucaria heterophylla), Norfolk Island, South Pacific

9. 3653 - 20th Primrose tree (Lagunaria patersonia), Norfolk and Lord Howe islands (soft pink flowers will begin appearing soon)

Guerrero Street, 20th to Liberty, east side

10. 823 Guerrero Mulberry (Morus alba), China (tree is across the street; the large leaves are the only food of the silkworm, from whose cocoons we get silk thread)

11. 827 Guerrero Cabbage tree (Sonchus brassicifolius), Juan Fernandez Islands, Chile (short tree with large roundish lives, just above the wall; extremely rare in SF)

12. 827 Guerrero Blue Atlas cedar (Cedrus atlantica ‘Glauca’), Atlas Mountains of Morocco & Algeria

Liberty Street, Guerrero to Valencia, north side

13. 845 Guerrero Ginkgo (Ginkgo biloba), China (these 3 trees are all females; note the fruits developing; when ripe, they will be exceedingly foul-smelling)

14. 82 Liberty New Zealand Christmas tree, pōhutukawa in Māori (Metrosideros excelsa), New Zealand (this tree flowers most reliably in summer months, which would be Christmas time in NZ, south of the equator)

15. 82 Liberty Indian laurel fig (Ficus microcarpa ‘Nitida’), S Asia to N Australia (formerly one of SF’s most planted trees)

16. 50 Liberty Shamel ash (Fraxinus uhdei), Mexico to Central America (much of the street is planted with these trees, many of which were pollarded at some point in their lives)

**Continue south on Valencia to 21st

21st Street, Valencia to Guerrero, south side

17. 3325 - 21st Lemon bottlebrush (Callistemon citrinus), E Australia (a row of several trees)

** Note the row of beautiful ginkgos in the middle of this block

Guerrero Street, 21st to Hill, east side

18. 906 Guerrero Douglas fir (Pseudotsuga menziesii), West Coast & Rocky Mountains to S Mexico (tall conifer with needle-like leaves across the street; a CA native tree!)

19. 940 Guerrero Camphor trees (Cinnamomum camphora), E and SE Asia (two trees across the street, recently pruned to be quite open; this tree prefers more summer warmth and is seldom planted in SF)

20. Guerrero median Shoestring acacia (Acacia stenophylla), Australia, mostly in the interior of the continent (many trees are planted in the median for several blocks of Guerrero; long slender leaves)

Hill Street, Guerrero to Valencia, south side

21. 99 Hill Jacaranda (Jacaranda mimosifolia), Argentina, Bolivia, Brazil (watch for the big show of blue purple flowers soon; these heat loving trees are becoming more common in SF, especially in warmer areas like the Mission District—all thanks to climate change)

22. 949 Guerrero Raywood ash (Fraxinus augustifolia ‘Raywood’), C & S Europe, NW Africa, SW Asia (tree is on the north side of Hill Street; a selected seedling found in a South Australia garden)

23. 87 Hill Japanese camellia (Camellia japonica), E Asia (though usually grown as a shrub for its beautiful late winter/spring flowers, Japanese camellia is actually a small tree; note shrubby forms in front of the neighboring house)

Beautiful Mexican marigold (***Tagetes lemmonii)*** on the north side of Hill Street

24. 83 Hill Purple-leaf plum (Prunus cerasifera), Eurasia (pink flowers usually appear by February; formerly SF’s most planted street tree; totally without leaves through fall and winter)

25. 53 Hill London plane tree (Platanus x hispanica, formerly Platanus x acerifolia), hybrid of E USA species and European species; it is among the most commonly planted trees in cities around the world)

26. 49 Hill Japanese maple (Acer palmatum), Korea and Japan

27. 41 Hill Marina strawberry tree (Arbutus ‘Marina’), hybrid of Mediterranean species (this hybrid was first introduced in San Francisco)

Closeup of flowers of Marina strawberry tree (*Arbutus* ‘Marina’)

28. 25 Hill Australian willow or wilga (Geijera parviflora), E & SE Australia (this tree generally prefers the warmth of the eastern parts of the city). This is the best example of this species in San Francisco that we’ve found!

29. 1 Hill Mexican fan palm (Washingtonia robusta), Baja California & Sonora, Mexico (2 trees trees with short trunks; California’s most commonly planted palm)

Valencia Street, Hill to 22nd, west side

30. 1098 Valencia Brisbane box (Lophostemon confertus), E Australia

22nd Street, Valencia to Guerrero, north side

31. 1098 Valencia Hybrid Fogg michelia (Magnolia x foggii), hybrid of Asian species, M. figo and M. doltsopa (tree is on 22nd; watch for fragrant white flowers opening from the furry brown buds)

32. 3326 - 22nd Paradox walnut (Juglans hindsii x J. regia), hybrid of CA native and European species (2 trees; be sure to read the story about them in the shop window)

33. 3334 - 22nd Prickly melaleuca (Melaleuca styphelioides), E Australia (note the tiny prickly leaves, white flowers, and spongy park)

34. 3342 - 22nd Ginkgo (Ginkgo biloba), China (one of SF’s best specimens)

35. 3368 - 22nd Jewel yucca (Yucca gigantea ‘Jewel’), Central America (in the bright yellow containers; note the striped, or variegated, leaves)

The Lone Palm of the Lone Palm!! Mule palm (*Butia odorata* x *Syagrus romanzoffiana*)

36. 3394 - 22nd Mule palm (Butia odorata x Syagrus romanzoffiana), a hybrid of Brazilian species (very uncommon)

I love the doorway of the Lone Palm bar :)

22nd Street, Guerrero to San Jose, south side

37. 1001 Guerrero Giant yucca (Yucca gigantea, formerly Y. elephantipes), Mexico & Central America (tree is on 22nd Street; all-green leaves)

38. 3365 - 22nd Victorian box (Pittosporum undulatum), E Australia (intensely fragrant white flowers cycle through the year)

39. 3345 - 22nd Red maple (Acer rubrum), Eastern North America

**Head south on San Jose Avenue, turning right on Alvarado Street

Alvarado Street, east of San Jose, north side

40. 36 Alvarado Natchez crape myrtle (Lagerstroemia x ‘Natchez’), hybrid of E Asian species (developed by the National Arboretum in DC; notable for its beautifully mottled bark, outstanding fall color, and its mildew-resistant foliage, making it a good choice for SF; its flowers are white, in late summer)

*** Cross Alvarado carefully***

Alvarado Street, east of San Jose, south side

41. 37 Alvarado Queen palm (Syagrus romanzoffiana), S Brazil

42. 50 San Jose Southern magnolia (Magnolia grandiflora), SE USA (2 trees on Alvarado Street)

**Continue south on San Jose to 23rd Street

San Jose Avenue at 23rd, west side

43. 3503 - 23rd Silver Atlas palm (Chamaerops humilis var. argentea), Atlas Mountains of Morocco & Algeria (trees are above the wall on San Jose; low, shrubby palms with silvery cast to the foliage)

44. 3503 - 23rd Waggie palm (Trachycarpus fortunei ‘Wagnerianus’), cultivar of a Chinese species (taller palms above the wall on San Jose)

Knife-leaf wattle (Acacia cultriformis), E Australia (row of small trees above the wall on San Jose; watch for yellow flowers in winter)

45. 3503 - 23rd Pasopaya palms (Parajubaea torallyi), Bolivian Andes (5 trees in a row along San Jose; very rare)

This tree walk ends here. To return to its beginning, head back to Valencia and turn left; follow Valencia back to 19th and turn left toward the Mission Pool.

Our regular commercial: This walking tour was organized by Mike Sullivan, author of The Trees of San Francisco and webmaster of www.sftrees.com; Jason Dewees, horticulturist at Flora Grubb Gardens and author of Designing with Palms; Richard Turner, retired editor of Pacific Horticulture magazine and Sairus Patel, soon to be author of Trees of Stanford and Environs. You can follow Mike and Jason on their tree-themed Instagram pages at @sftreeguy and @loulufan. Richard edited another great book on San Francisco trees: Elizabeth McClintock’s Trees of Golden Gate Park. If you’re a tree enthusiast, buy all four of these books!

New Zealand Christmas trees at peak bloom

July 04, 2023 by Michael Sullivan

New Zealand Christmas trees (Metrosideros excelsa), known as pōhutukawa in their native New Zealand, love San Francisco’s cool maritime climate - and they’re in full bloom right now (early July - a little bit late this year!). New Zealand Christmas trees are in the myrtle family, and are relatives of the eucalyptus and other trees with “bottlebrush”-type flowers (what you’re seeing in the flowers are not petals, but the male stamens of the tree). Almost all of the thousands of New Zealand Christmas on the streets of San Francisco have red blooms, but there’s one tree at 1221 Stanyan Street in Cole Valley that puts on a show with eye-popping yellow flowers.

How did this tree end up with yellow flowers? The story goes back to Victor Reiter, San Francisco’s most famous plantsman from the 1940s until his death in 1986. In 1940, there was a natural mutation of the species on tiny Motiti Island in the Bay of Plenty in New Zealand. Reiter was one of the first Californians to obtain a cutting - from a friend who happened to be visiting New Zealand. As the Reiter family lived in several homes in a three-block stretch of Stanyan Street, they planted the curiosity in front of their 1221 Stanyan address—still occupied today by a family member. And more than 70 years later, the tree is thriving. It’s a beautiful mutant with an amazing history and pedigree—and my favorite tree in San Francisco.