San Francisco Trees

SALESFORCE PARK WALKING TOUR

The rooftop park on the Salesforce Transit Center (four blocks long, between Mission and Howard and 2nd and Beale Streets) is a spectacular amenity – a 5.4 acre botanical garden and arboretum that was dropped into the city’s financial district when it opened in August 2018. It’s not just a pretty park - it’s the best collection of trees and plants in San Francisco outside of the botanical garden in Golden Gate Park.

As wonderful as the park is, I’ve heard from many visitors that they wish the trees and plants in the garden were identified or labeled.  So I decided to help.  The self-guided walking tour below is my contribution to those who love the park, but wish they knew more about what they were seeing! 

Much of what I am sharing below I know because Adam Greenspan, the landscape architect at PWP Landscape Architecture who led the design of the park, was kind enough to give me a personal tour of the park just before it opened.  Greenspan did an amazing job curating hundreds of trees and thousands of plants from around the world, and grouping them in themed gardens (a Chilean garden, a South African garden, and so on), leaning heavily on plants from Mediterranean regions around the world that will thrive in our northern California climate.  His deep plant knowledge and interest shines everywhere in the park. 

From the ground floor of the transit center, ascend the escalator until you reach the top level.  Turn right, and continue until you reach the path that circles the park.  On your right will be a grove of Brisbane box trees from Australia (or Lophostemon confertus if you’re a botanist), one of San Francisco’s most common street trees.  Interspersed among the trees are small cycads, also native to Australia (they look like very short, small palms – the scientific name is Macrozamia communis).  Turn left at the pathway to begin a tour of the park’s palm garden.  

On your immediate left are a grove of kentia palms (Howea forsteriana) and sentry palms (Howea belmoreana), both from Lord Howe Island, east of Australia – they’re the palms with the striped trunks; the two species look similar but the three palms closest to the corner of the garden are the sentry palms. Just past these palms is a grouping of six Nikau palms (Rhopalostylis sapida), New Zealand’s only native palm – you’ll see them just before you reach the exit sign leading to stairs on your left.   Just a bit further on the left is another grove of six palm trees that look similar to the Nikau palms, but they are a closely related species - Norfolk Island palm trees (Rhopalostylis baueri), native to Australia’s Norfolk Island.

As you continue, on your left you’ll pass a number of palm trees of different species, but behind them you’ll see a large palm in the lawn with very large trunk.  It’s one of the most spectacular trees in the park - a Chilean wine palm (Jubaea chilensis), native (of course) to Chile. This species is the second most massive type of palm in the world, but it’s very slow growing, so it’s impressive to have such a large one here in the park.  

This palm garden is a ten-car pileup of different species - it’s too hard in this tour to identify them, but among the trees you’ll see are three ribbon fan palms (Livistona decora) from Australia and 15 Guadalupe palms (Brahea edulis) from Guadalupe island (these two species are to the north, on the other side of the glass wall past the bus fountain), Mexican blue palm (Brahea armata ‘clara’) from Baja California, Quito palm (Parajubaea cocoiodes) from Ecuador and Columbia, kumaon palm (Trachycarpus takil) from northern India and Nepal, and miniature chusan palm (Trachycarpus wagnerianus) from the foothills of the Himalayas.

One species that’s easy to ID are the smaller, multi-trunked palms in the garden - these are Mediterranean fan palms (Chamaerops humilis) from North Africa and southern Europe - the northernmost palm species in the world. 

The last palm tree on your left in the palm garden – rather large, with graceful curved fronds, is a pindo palm (Butia odorata) from southern Brazi and Uruguayl. Continuing on the path, on your left you’ll see a glass dome ringed by tall palm trees – these are fan palms (Washingtonia X filibusta) – a hybrid of the Mexican fam palm (Washingtonia robusta - the tree that lines Mission Street in the Mission District) and the California fan palm (Washingtonia filifera). 

Soon you will then cross two white stripes on the path – marking a seismic stability feature.  The Salesforce Terminal is actually three buildings, and the white stripes mark the gaps between the buildings – in an earthquake the gap is intended to break the wave energy of the earthquake.  Just past the stripes, on your left are several gnarled African sumacs (Rhus lancea) from South Africa, followed by a Monterey cypress (Hesperocyparis macrocarpa), native to California’s central coast, near Carmel (and very common in San Francisco’s parks), and then a small California buckeye (Aesculus californica), which is a Bay Area native.  We’re in a small grove of California natives at this point - on your right, directly across from the Monterey cypress, on the other side of the glass wall are five fernleaf Catalina ironwoods (Lyonothamnus floribundus ssp. Asplenifolius), native to San Clemente, Santa Rosa and Santa Cruz Islands off the Coast of Southern California . 

Continue past the exit sign. On your right, on the other side of the glass wall, and one also at the very end of the sidewalk fountain, are several strawberry trees (Arbutus X Marina).  I suppose we can consider this tree a California native as well - it’s a natural hybrid of two Arbutus species from the Mediterranean, but the hybrid was first discovered in the 1915 Panama-Pacific International Exposition in Golden Gate Park, which got the trees from the closing sale of a nursery in San Francisco’s Marina district – hence the name (and if you’re really interested in the SF story of this popular hybrid, click here. It was later introduced to the nursery trade, and is now one of the most commonly planted street trees in San Francisco.   Continue past some Japanese maples (Acer japonica) on your left. The two pine trees on your right are torrey pines (Pinus torreyana), native to Southern California, followed by two more Monterey cypress trees, and then two island oaks (Quercus tomentella), an endangered tree that is native only to the Channel Islands in southern California and Mexico’s Guadalupe Island. This ends the California native garden.

Continuing on the path you’ll see the first of a large number of narrow, vertical European hornbeam trees (Carpinus betulus 'Fastigiata') which line the lawn for large portions of the park. Continue until you reach the desert garden at the western end of the park – filled with cacti and other succulents. The “stars” of this garden are the palm-like dragon trees (Dracaena draco), native to the Canary Islands, Madeira and Cape Verde - there are three of them in this garden.

The path now turns left as you head south, until you reach the second desert garden on your right. This garden is full of aloes, as the signage explains. The large tree-like aloes are Tonga tree aloes (Aloe tongaensis ‘Medusa’) from South Africa and Mozambique.  

The path now turns again to head east, where you’ll reach the park’s “fog garden”, full of plants that have evolved to use fog to survive.  The first tree here (just past the “Fog and Wind Garden” sign on the right, is a pink melaleuca (Melaleuca nesophylla) from western Australia – a shrublike tree with pink flowers if it’s in bloom.  Western Australia, near Perth, has a “Mediterranean” climate like California - very little rain in the summer, and mild winters.

Walk past the two buildings on your left, and pass the “cloud forest” sign on your right. You’ll soon come the same seismic joint that I mentioned earlier - and this time there’s signage to explain it! Now you are entering the Chilean garden of the park. The first tree past the seismic joint, on the right, is a mayten tree (Maytenus boaria) from Chile; there are also three other Maytens in the lawn behind you and to the left. Theses trees have a drooping habit that reminds many of weeping willows. Chilean cows love the foliage, which is where the scientific name comes from - “boaria” means “of cattle”, or bovine, in Latin.  Further down on your right you’ll see three striking monkey puzzle trees (Araucaria araucana).  You can’t miss them – they are the trees with the spare, symmetrical shape and sharp, scaly leaves.  These trees are native to Chile and western Argentina.  (The common name of the tree dates back to 1850, when the tree was still rare in England - the proud owner of a monkey puzzle in a garden in Cornwall showed it it to a group of friends, and after noticing the sharp branches, one of them remarked, "it would puzzle a monkey to climb that”! And the name stuck.) If you look to the left of the path, you’ll see some close botanical relatives of the monkey puzzles – three cook pines (Araucaria columnarisi) in the lawn (they look like Christmas trees).  Cook pines are native to New Caledonia in the South Pacific, and are in the same Araucaria genus as the monkey puzzles – think of them as siblings in the plant world. 

As you continue, the large tree with the round crown in the lawn on your left is a Chinese elm (Ulmus parvifolia), native to eastern Asia, and San Francisco’s most commonly planted elm tree. [November 2021 update - sadly, the tree lost a third of its crown in the severe October storm that hit the Bay Area.] There are two others nearby in the lawn.  

Now you’ll enter the South African garden on your right (like Chile, South Africa has a Mediterranean climate, so its plants are often successful in the Bay Area).  The first trees in this garden are three silver trees (Leucadendron argenteum), with distinctive silvery green leaves. This species (called silwerboom in Afrikaans) is endangered in the wild; it’s native to a very small area near Capetown.  Just past the silver trees are a number of agapanthus plants (with blue flowers in full bloom as I write this in July). Agapanthus are so common in the Bay Area that native born Californians dismiss them as common and boring - my in-laws call them the “freeway bush”. But we had nothing like them when I was growing up in Upstate New York - and they really thrive here, so I’m a fan.

Continue past the children’s play area on your left.  On on your right as you pass the climbing gym are three Henkel's yellowwood (Podocarpus henkelii), native to South Africa, and South Africa’s national tree. Further along on the right are three very large Queensland bottle trees (Brachychiton rupestris), the trees with the narrow leaves and swollen trunk at the base (the swollen trunks are an adaptation to dry climates - they allow the tree to store water during rainy periods, which can be drawn upon during drought periods). Further along, but close by on your right, you’ll see two more trees, also with large trunks but with maple leaf-shaped leaves – these are also in the Brachychiton genus; the first tree is a kurrajong (Brachychiton populneus) and the second is a flame tree (Brachychiton acerifolius).   The flame tree gets its common name from the bright red bell-shaped flowers that often cover the entire tree when it is leafless. 

Continue to the plaza, with tables and chairs on your left. The trees in the plaza are California sycamores (Platanus racemosa ‘Roberts’), a native California tree, common in riparian valleys from the Bay Area south to Baja California.  It is rare on San Francisco streets – these trees are a bit of an experiment. As you continue, to the right of the path are two champak trees (Magnolia champaca), native to the Indian subcontinent and southeast Asia.  Another common name is “joy perfume tree” – the flowers of the tree are very fragrant.  As you continue east, you will pass a multi-trunked olive tree (Olea europaea), and just past some low-lying reddish smokebush (Cotinus coggygria) another strawberry tree. 

As you continue on your right you’ll see a sign for “Mediterranean gardens of the world”. The palms near the sign are Mediterranean fan palms (the same species that we saw in the palm garden earlier). The next trees on the right, with the grey furrowed bark, are cork oaks (Quercus suber), native to Portugal, Spain and other spots in the western Mediterranean – the bark of this tree is the source of the cork used in wine bottles.  

 Continue until you see the entrance to a building on your left (the building is 181 Fremont – which holds Instagram’s headquarters on its lower floors, including this one; Andytown Coffee Roasters is just inside and open weekdays if you need a break).  To the left of the path just before you reach the 181 Fremont entrance is a Persian ironwood (Parrotia persica), native to Iran and Azerbaijan - it’s the tree with the vertical cracks in its trunk.  

Now, on your right, you’ll enter the prehistoric garden, one of my favorites in the park. Most of the trees and plants here date back millions of years, to the time when dinosaurs roamed the earth.  The first tree on the right is a ginkgo (Gingko biloba), followed by two small champak/joy perfume trees, followed by another ginkgo. Then you’ll reach some spectacular giant cycads (from the Encephalartos genus - the largest one is Eastern Cape Giant Cycad (Encephalartos Altensteinii) from South Africa - I think they’re among the most impressive plants in the park.  Next (a young tree - still staked) is a Queensland kauri tree (Agathis robusta), native to northern Australia and New Guinea, followed by two more monkey puzzles trees.  

The next tree in the prehistoric garden is my favorite in the entire park. It doesn’t jump out at you – it’s the evergreen tree that is perhaps seven feet tall, four feet wide, with graceful pinnate leaves, just past the “TransBay Mammoth” sign.  I love it for its recent history:  scientists knew this tree from fossil records, but assumed that it had been extinct for millions of years.  Until … September 10, 1994, when David Noble, an Australian park ranger with some botanical knowledge, bushwacking in a remote canyon in Wollemi National Park near Sydney, discovered a grove of trees he didn’t recognize.   He brought some specimens back to Australian scientists, who identified it as the same tree they knew from fossils.  (Imagine finding a few Stegosaurus hanging out in a remote New Guinea jungle - for botanists, it’s like that.) Fewer than 100 specimens survive in the wild in three groves (the location of the groves is undisclosed, to protect the trees).  Scientists named the tree Wollemi nobilis to honor Noble. The common name is Wollemi pine, although the tree is not a true pine – it’s actually in the Araucaria family, more closely related to monkey puzzles and Norfolk Island pine trees.     

As you turn the corner and head left (north), you will see three river birches (Betula nigra), native to the eastern United States, in a circular planting in the corner of the park. The low lying plants with gigantic leaves in this garden are Gunnera chilensis, known as giant rhubarb, or - my favorite common name in the park - dinosaur food (it’s an ancient plant).  As you reach the northern end of the path, you’ll see three more river birches on your right. The irises in this garden are “walking iris” (Neomarica caerulea). The flowers of this plant are followed by plantlets that grow in weight until they hit the ground, allowing the plantlet to root (or walk) away from its parent.   

Turn the corner and head west back to your starting point.  On your right - the tree with droopy branches - is a deodar cedar (Cedrus deodara) from the Himalayas, followed by an incense cedar (Calocedrus decurrens) native to California and Oregon, and then behind the incense cedar, a torrey pine (these three species are repeated in the garden on the right for a while).  

The large tree with furrowed bark opposite the beginning of the bus fountain is a southern live oak (Quercus virginiana), native to the American southeast. 

As you continue on your right, on the other side of the glass wall, you’ll find another deodar cedar, followed by seven coast redwoods (Sequoia sempervirens), the tallest tree in the world and the redwood that is found in Muir Woods and coastal northern California.   There are several coast redwoods on your left as well.

Walk past the gondola on your right, and you’ll approach the entrance to the Salesforce Tower on your right. Only Salesforce employees are allowed to enter the tower here, but there’s a Starbucks that’s accessible to the public.  The unusual vertical looking trees on either side of the entrance to the tower are actually giant sequoias – the gigantic trees from the Sierra Mountains.   Here, the landscape designer chose a variety that has a vertical, fastigiate shape (Sequoiadendron gigantea ‘Pendula’).  Just past the giant sequoias, you have Brisbane boxes on either side of you – the trees that we saw at the beginning of the tour.   Continue until you return to your starting point where you can turn left and take the escalator back to the street. 

Small advertisement:  if you enjoyed this tour, my book, Trees of San Francisco, has 12 more tours of interesting San Francisco neighborhoods, taking you past landmark trees (and some quirky only-in-San Francisco non-tree stuff that I’ve discovered).   There are tours of the Mission, Potrero Hill, Pacific Heights, the Castro, Noe Valley, the Presidio, Cole Valley, Forest Hill, the Financial District, Parnassus Heights , the Golden Gate Park panhandle, and Upper Market’s staircase streets – a dozen tours in all.   And descriptions of 70 trees that you’re likely to find on San Francisco streets.   Available on Amazon, or even better at your neighborhood bookstore!

I put another walking tour of the park on youtube - search for “Salesforce Park Tree Tour” to find it. And for more tree-related stuff, click on the links at the top of this page - my tree blog, my list of San Francisco’s top 10 landmark trees, etc. - or follow me on Instagram @sftreeguy.