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Sign up to take an arborist-led Tree Walk. Tree Walk starting point map.
~ Hoover Park, near the tennis courts
The Blue Gum is a widely cultivated tree in Australia, but considered an invasive species in California. The tree is known as Blue Gum for its blue-grey, waxy leaves that are used to extract eucalyptus oil. The bark sheds in large strips, and cream-colored flowers produce honey.
~ 2802 Cowper St, near corner of El Dorado
This misnamed tree is native to Western Peru, where it can grow at elevations of up to 10,000 feet. Brought to California in the 1830s, this fast-growing, drought-tolerant tree is best grown in dry conditions to avoid root rot problems.
~ 2796 Cowper St, on El Dorado near fence
Contrary to its common name, it is also native to Peru. The dark green glossy leaves are divided into 5-13 oval leaflets. Its bright red berries are very showy in winter and are sold as pink peppercorns. Listed by California Invasive Plant Council (CAL-IPC) as an invasive exotic, especially near riparian areas.
~ 500 Colorado Ave, right side on Cowper
This is an edible fig, ‘Black Mission’ and ‘Brown Turkey’ are consistently good local varieties. Tolerates some drought, but best fruiting is achieved with light supplemental watering. Figs achieve their best form with some space.
~ 2601 Cowper St, right side
“California’s mightiest oak,” according to Sunset’s Western Garden Book. No other native oak in California matches the sheer size and spread of an old Valley Oak. Valley Oaks and Coast Live Oaks were the predominant native trees in Palo Alto prior to development A Valley Oak should dictate the other landscaping around it. Irrigation within the root zone will cause root crown fungus to develop, leading to death of the tree.
~ 2596 Cowper St, right of driveway
This fast-growing deciduous tree resembles an umbrella as it matures. In summer it is covered with fluffy pink flowers. The flowers are a bit messy, so the tree is best planted among planting beds. It attracts birds to the garden and is native throughout Asia from Iran to Japan.
~ 2579 Cowper St, right and left sides of yard
This large, majestic tree, native to the Atlas Mountains of Morocco and Algeria, was used for shipbuilding in ancient Greece. Needles cluster on the tops of the branches and its shorter, stiffer needles distinguish this cedar form the Deodar Cedar. It needs a large area for full development and should not be crowded. Its wood has a strong scent that repels insects and is excellent for carpentry.
~ 2540 Cowper St, center front yard
This wonderful, large specimen is at least 200 years old. The Coast Live Oak is an evergreen native throughout much of California. They grow relatively quickly to 70′ with an equal spread. Once established, they tolerate drought very well; summer watering should be avoided.
~ 2512 Cowper St, 4 trees near the street corner
The Coast Redwood is America’s tallest tree and lives to well over 1,000 years. Locally, only the landmark Coast Redwood called El Palo Alto is that old. Most local Coast Redwoods were logged by the early 1900s, to help rebuild San Francisco after the 1906 earthquake. Although redwoods are protected by Palo Alto city ordinances, they should no longer be considered suitable trees to plant, due to their excessive water requirements and poor drought tolerance.
~ 2499 Cowper St, street tree on corner
A graceful, fine-textured tree from Australia. The foliage is similar to the Weeping Willow, but it is unrelated. It is no longer recommended for planting because of structural problems and poor performance. Trees that grow to maturity tend to have structural issues.
~ 485 Marion Ave, front yard center
This deciduous oak from the northeastern US grows quickly to 60-80′ high and 40-60′ wide. Fall color ranges from yellow to shades of orange and scarlet red. This species tends to hold its brown dormant leaves well into winter. The Scarlet Oak grows deep roots and is planted as a street tree in a few areas of Palo Alto.
~ 475 Marion Ave, near right corner of the house
If a tree is blooming bright purple during summer, you can bet it’s a Jacaranda. A popular street in Santa Barbara, this Brazilian native sports large clusters of purple flowers all summer, followed by disc-like seed pods. A deciduous tree with delicate fernlike leaves, Jacarandas are a bit frost-sensitive.
~ 400 block Marion Ave, dominant street tree
The most common street tree on this block is the Camphor, from China and Japan. The new leaves of the evergreen tree are often tinged with pink or red. Crushing the shiny leaves gives a camphor odor. Because of its habit of lifting sidewalks, Camphors are no longer considered appropriate street trees in Palo Alto.
~ 2501 Waverley St, left of the house
The distinguishing characteristic of this pine is the needle growth. In bundles of three, new needles point upwards and old needles downwards. As the common name implies, they are native to the Canary Islands, and are an excellent substitute for Monterey Pines. It’s resistant to oak root fungus, relatively pest free, and drought tolerant when established.
~ 2510 Waverley St, street tree at center
Italian Stone Pines have been cultivated for at least 6,000 years for their edible seeds, called pignolis. In maturity, they have large, relatively short trunks, and broadly spreading, umbrella-shaped crowns. They require a great deal of space to properly mature. (The tree to right is a Monterey Pine.)
~ 2563 Waverley St, front right by driveway
Windmill palms are short, compared to other palms, and can be easily identified by their hairy trunks. Although their flowers are inconspicuous, they are noticeably fragrant. This is an unusual specimen with 7 trunks.
~ 2563 Waverley St, next to driveway
Eastern Redbuds are thirstier cousins to our native Western Redbud. Redbuds are known for their late winter display of bright pink, pealike flowers covering their bare branches. In summer, the delicate branches sport heart-shaped leaves. Fall color varies from yellow to orange.
~ 2580 Waverley St, 3 trees on right side
Junipers were very popular landscaping plants in the 1960s, but have fallen out of favor in recent years. Hollywood Junipers are a tree form of juniper that has a windswept form even without the wind. Its twisted form becomes more impressive as it ages.
~ 2599 Waverley St, many trees in yard
This yard has an extensive collection of Japanese Maples that demonstrate the great variety in form, leaf shape and leaf color of Japanese Maples.
~ 2599 Waverley St, Colorado side yard by fence
Persimmons are wonderful, small to medium garden trees. Besides their tasty fruit, persimmons have terrific fall color, their large, glossy leaves glowing in electric orange. This ‘Hachiya’ cultivar produces astringent, acorn-shaped fruit, which must be left to ripen after it is picked.
~ 445 Colorado Ave, right of driveway
Native to the Sierra Nevada, the vertical sprays of foliage and peeling bark are a unique identifying features. They are lovely and interesting conifers, native to the Sierra Nevada and Cascade mountains. They tend to struggle in the Bar Area.
~ 464 Colorado Ave, corner of Kipling
The trunks of Carob trees are gnarled, burly, and twisted. The almost round, dark green, glossy leaflets densely cover the tree. Female trees have hard, 6″ long seed pods that contain edible seeds used as a chocolate substitute. This evergreen tree is extremely drought-tolerant, and easily maintained as a smaller street tree.
~ 2642 Kipling St, dominant street tree
Popular street tree from the 1950s-1960s, Modesto Ashes were thought to be bullet-proof. Unfortunately, their narrow branch angles cause limbs to split off. No longer planted in Palo Alto, the Autumn Purple Ash is a current substitute.
~ 2712 Kipling St, back right corner of yard
Native to Australia and New Zealand, this small tree is called tea tree because Captain Cook brewed tea from its leaves and gave it to his crew as a scurvy preventative. It grows to 10-13′ with finely textured foliage and blooms in the spring.
~ 470 El Dorado Ave, center of front yard
A medium-sized, round-topped tree with small dark purple fruit and yellow leaf color in fall. The bark is smooth with warty protuberances. Honeydew from wooly hackberry aphids can make a mess, and the roots can cause sidewalk damage.
~ 475 El Dorado Ave, center front
Formerly known as Sapium sebiferum, the Chinese Tallow is a smaller deciduous tree with wonderful fall color, in yellows, oranges and reds. Listed by CAL-IPC as an invasive exotic tree.
~ 485 El Dorado Ave, by driveway
The glossy leaves and somewhat rougher bark of this tree distinguishes it from the European Hackberry. Inconspicuous flowers are followed by orange, quarter-inch fruits that hang from stems on this fairly drought-tolerant shade tree. Palo Alto stopped planting this tree due to pest issues.
Trees protected by the City of Palo Alto tree ordinanceA permit is needed to remove or prune these trees.
Check the City of Palo Alto Tree Regulations.
Trees with low watering needsThese trees are best adapted to our climate and water availability.
Thirsty treesThese trees require frequent summer irrigation and will suffer from the drought cycle in our area.
Do not plant unless you are aware of a water source such as high water table or creek proximity.
Trees not recommended for plantingThese trees are either invasive, do not perform well or create infrastructure or other problems.
