Native Trees

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COAST LIVE OAK
Quercus agrifolia
 photo by: Picasa/Akira
Large evergreen oak, spreading, attractive branch pattern, deep green, rounded, holly-like leaves.  Probably the best tree for local propagation.  Bark on trunk and limbs smooth in young trees, becoming roughened and furrowed with age.

Planting:  Park shade tree.  Faster and better growth when planted than when inherited as seedling from nature, although the latter should be fostered.  May be grouped as closely as 6' to create woodland grove.  Can grow well in many kinds of soils.

Local
:  Examples are common.  The larger evergreen in Ford Park, and two next to red schoolhouse are fine examples.  Younger trees border Westridge Drive.

BLACK OAK
Quercus kelloggii   
 photo by: WW Hansen
Large deciduous oak, branching high to 70’ or more, with broad, rounded top. The dark shiny leaves deeply lobed, the lobes toothed. In autumn the leaves turn yellow, sometimes very colorfully on the descending mountainside ridges. This is a mountain oak, not found here below 350’ elevation.

Planting: Becomes a large tree slowly. Best planted with other oaks for shade in early life. Local occurrence suggest well drained soil habitat.

Local
: Both sides of upper Cervantes Drive between Fawn Lane and Westridge Drive, and by Alpine Road opposite Corte Madera School. Fine specimen on upper side of Bolivar Lane about 150’ from Westridge Drive. Common in Corte Madera canyon, along Alpine Road.

VALLEY OAK
Quercus lobata
 photo by: lortonb@gmail.com
Large deciduous oak with lobed leaves and rough grey bark. Mature trees with beautiful tortuously spreading limbs. The large, widely spaced, deciduous oak of our grass lands.

Planting: Shade tree best as a single specimen or widely and irregularly spaced in open grassland areas. Slow growing, but it is thought to be the largest oak in America.

Local
: A common tree. Old specimens may be seen with Live Oaks in Ford Park, and on the grounds south of red schoolhouse.


COAST REDWOOD
Sequoia sempervirens
 photo by: Picasa/WhisperOak
Towering, fast-growing symmetrical tree. Leaves are dark green needles. Bark furrowed deep reddish brown on older trees. Roots spread and feed near surface which in the forest are covered by dry needlefall. Under favorable conditions in well watered areas will grow from 2’ to 5’ per year.

Planting: Needs water. Does best in partially shaded areas, and when planted in groves or circles from 10’ to 50’ in diameter. Grows rapidly. Practically pest free.

Local: May be seen at entrance to The Sequoias, and behind Ormondale School atop the creek bank. A fine grove may be seen along Portola Road at the entrance to the Morshead Ranch, “El Mirador,” and in the surrounding areas.


DOUGLAS FIR
Pseudotsuga menziesii
 photo by: Washington State University
Tall, usually dense conifer, conical in youth, older trees with picturesque branching-short needles, small attractive cones. Most of the tall separately growing conifers on the mountainside are Douglas Fir.

Planting
: Does best in oak woodland habitat or partially shaded area. Locally grows frequently at the edge of oak forest. Relatively drought-tolerant after established.

Local
: This fine conifer unfortunately is not well represented in town. The best are to be seen above Alpine Road on the mountainside.


CALIFORNIA BAY LAUREL
Umbellularia californica
 photo by: Picasa/Su
Dense, tall tree sometimes spreading. Leaves evergreen 4-5 inches long-shiny smooth, deep yellow-green; strongly scented spice. Bark smooth to slightly roughened. In winter most branches end with many clusters of small cream-colored flowers.

Planting
: Grows best in shaded areas or in well watered places. Locally common along creeks and in bottomland, but large specimens or clusters also appear on north-facing brushy slopes as solitary figures.

Local
: Common along Los Trancos Creek bank from Ford Park to Highway 280. Small trees on north corner of Bolivar Lane and Westridge Drive intersection. Virtually pest free. Purported fire retardant.

BIG LEAF MAPLE
Acer macrophyllum
 photo by: pauly1766
Tall, spreading, fast-growing deciduous tree. Excellent horticultural maple-fast growing. Leaves to over 6 inches across, forming a dense canopy in summer. Bark smooth, grey.

Planting
: Requires moisture. Best in well-watered low areas, or in well attended places. Fine specimen trees, or may be grouped at ten or more foot intervals. Easily grown in moist areas from slips to 4’ long.

Local
: Best seen in the corridor between Alpine Road and Corte Madera Creek where it is abundant.

MADRONE
Arbutus menziesii
 photo by: ramblingfolks.net
Grows to tall, spreading evergreen broadleafed tree, often beautifully and grotesquely branched. The smooth, beautiful, deep reddish bark peels in thin flakes. Leaves are shiny dark green above, paler beneath. 2” across and over 5” long. In early spring there are bunches of inverted urn-shaped white flowers on the ends of branches, which in the gfall become clusters of bright red berries. Plant singly or in groups or mixed with live oaks.

Planting
: Use nursery specimens. Difficult to transplant from the wild. Once established can take moist habitat but is deep-rooted and when established can sustain drought for several years.

Local
: Small specimens grow commonly on sandstone banks along Cervantes Drive, and near where this drive intersects Westridge Drive.

ISLAY or WILD CHERRY
Prunus ilicifolia
 photo by: Las Pilitas Nursery
Small to medium-sized dense, holly-leafed tree or large shrub. Evergreen with glossy dark leaves. Early summer with clusters of creamy flowers in abundance. Bark smooth. Roots to great depth, and when established succeeds in dry areas.

Planting
: Tough dense screen or tall spreading dense cover. Serves well as background mass. Makes excellent hedge unpruned or formally sheared. Single specimens take on the shape of small live oaks 20’ to 30’ tall. Needs little care after becoming established.

Local
: Common locally in the wild, but unfortunately has been overlooked as a horticultural subject in Portola Valley. One 30’ roadside specimen tree by driveway, 219 Wyndham Drive.

CALIFORNIA BUCKEYE
Aesculus californica
 photo by: Picasa/Greg
One of the showiest and most beautiful native tree species because of its great masses of creamy white flowers that appear along erect spikes in the spring. Native to canyon slopes and along hill streams. Its leaves are bright green. Small tree often shrubby but can reach 30’, with an open crown of wide spreading limbs. It loses its leaves in summer, and in the fall its bare smooth-barked trunks hold the large buckeye pods that eventually split to release an attractive, shiny brown buckeye seed, which resembles a nut but is poisonous.

Local
:  A nice specimen can be seen directly across from where Willowbrook Drive intersects Alpine Road.

BLUE OAK
Quercus douglassi
 photo by: Las Pilitas Nursery
Small to medium-sized deciduous oak with oval rounded leaves slightly lobed, dull bluish green on the upper surface. The bark is rough and gray. Mature trees often have straight trunks with lateral limbs. These trees are most common on the tops of hills in hotter, dryer locations

Planting
: An open tree producing dapple shade, they are best as single trees irregularly planted in open grassy areas. Very slow growing, this oak tends to grow where other oaks cannot grow because of the heat and dryness.

Local
: An uncommon tree in our area, found more commonly inland. Specimens may be found in the Blue Oaks Subdivision and in the higher parts of Westridge. Many hybridized with Valley Oaks.


Canyon Live Oak
Quercus chrysolepis                    
 Canyon Live Oak photo by picasa/s rowan
An evergreen oak often found in a shrubby growth form with significant spreading, horizontal branches, and a broad, rounded crown.  Its oblong leaves are flat, glossy dark green on the upper surface with prominent spines.  It is found in a variety of forest communities and is tolerant of a variety of soil types.


Tan Oak
Notholithocarpus densiflorus
 Tan Oak photo by courses.washington.edu
An evergreen hardwood tree (or shrub) with a great central trunk and crown varying from narrow and conical to broad and rounded.  The bark is brown, thick, and deeply ridged.  Leaves are thick and leathery, with oblong leaves and pointed tips.  The tree is generally found in moist valleys, mountain slopes and oak forests.


White Alder
Alnus rhombifolia
  White Alder photo by US NPS
A common, fast-growing, deciduous riparian tree that is not drought tolerant.  Leaves are alternate between rhombic and oblong forms.  Bark is smooth whitish to gray that becomes scaly as the tree ages.  The tree enjoys sun and water and has been found to grow even in creek beds. 






Photo credits are located here.