Description

Description:

Quercus agrifolia is a tree that grows 50 to 75 ft high, although 90 ft. is possible. In open conditions, it will develop an open structure without a central leader, often growing wider than it is high. The branches will grow down to the ground and often grow sideways along it. When the lowest branches are raised off the ground, this is due to shade, grazing, pruning or ground fire.

Coast live oak are resistant to low intensity fires. If cut or burned down, they can resprout from the base.

Branching:

Alternate.

Leaves:

The evergreen leaves are simple, without lobes. They are known for sharp prickles around the edge of the leaves. The term "agri-" in agrifolia means "fierce" or "wild".

The tree holds its leaves through winter. It sheds the old leaves in spring, after the new leaves emerge.

Bark:

Smooth bark on stems and small branches. Mature bark has irregular cracks and fissures.

Flowers:

The male catkins emerge in mid to late winter. The female flowers are minute and essentially invisible. I have never seen one.

Oaks are wind pollinated. The difference between a good acorn year and a bad one can depend on the amount of rainfall during flowering season. Too much rain can suppress pollination and the resulting acorn crop.

Fruit:

Coast live oaks produce acorns, normally ripening from late September into early November. The acorns will hold on the tree from a few days to a few weeks while they are ripe. Fully grown green acorns are ripe if they come out of their caps easily in October or November.

Productivity varies greatly from year to year. Most years have spotty or low production. Occasionally, you get a good acorn year, with many trees producing abundant crops.

Plant Relationships

Related California Species:

Red Oaks
Quercus chrysolepis
Quercus kelloggii
Quercus wislizenii

White Oaks
Quercus douglasii
Quercus dumosa
Quercus durata
Quercus engelmannii
Quercus garryana
Quercus lobata

(Canyon live oak)
(Black oak)
(Interior live oak)


(Blue oak)
(Scrub oak)
(Leather oak)
(Engelman oak)
(Oregon white oak)
(Valley oak

Related Species:

Quercus alba
Quercus macrocarpa
Quercus palustris
Quercus rubra
Quercus stellata
Quercus suber

(White oak)
(Bur oak)
(Pin oak)
(Red oak)
(Post oak)
(Cork oak)

Growing Conditions

Natural Range and Habitat:

Quercus agrifolia is found in the Coast Range and coastal zone in central and southern California.

When colonists first came to California, they noted that the oaks grew in open, parklike stands. This still occurs in many locations, but with the cessation of natural and prescribed fires, most oak stands have become quite dense. In many locations, especially north facing slopes, oaks are being replaced by California bay laurel (Umbellularia californica).

Sun and Exposure:

Quercus agrifolia is intolerant of shade. Near the coast, it is found in all exposures. As you go inland, and the climate getters hotter and drier, Quercus agrifolia tends toward north and east facing slopes as well as protected areas and riparian zones.

Soil and Moisture Requirements:

Coast live oak thrives in a wide variety of soil conditions, from sunny hillsides to riparian zones.

Horticulture and Restoration

Wildlife Habitat:

Coast live oak provides shelter for birds in their branches. Hollowed out sections in the trunk are used by birds, squirrels and other wildlife. The acorns are a major food source for wildlife. They can be eaten by humans, but must be treated to leach out their tannins before they are edible.

Restoration:

Quercus agrifolia is one of the most widely used plants in restoration because it is adaptable to a variety of site conditions and because it grows in so many habitats. In restoration, it can be introduced as acorns or supercells. It is generally more successful in larger sizes, such as dee pots or gallons.

Uses in Landscaping:

When using coast live oak in landscaping, ensure that it is in a full sun. Avoid watering near the root crown.

Horticultural Comments:

It is often said that you can't water an oak tree, however, plants that have been irrigated their entire lives can remain with irrigation. However, do not water an existing tree that became established without irrigation.

It is also said that oaks are slow growing. This can certainly occur, but in general, oaks grow as fast as any other tree if placed in a good location. When you install an oak tree, it takes two or three years to establish a root system, during which there is little top growth. After the root system is well established, the top resumes a normal growth rate.

Coast live oak, like other red oaks, is susceptible to Sudden Oak Death (SOD). One way to reduce the threat is to eliminate bay trees from the vicinity. There are other species as well that spread the disease to the oaks. Oaks are not capable of spreading the disease to each other.

Cronquist System

Order:

Fagales

Family:

Fagaceae

Genus:

Quercus

APG System

Order:

Fagales

Family:

Fagaceae

Genus:

Quercus