California Live Oak (Agrifolia)

The California Live Oak (Agrifolia) is generally described as a perennial tree or shrub. This is native to the U.S. (United States) has its most active growth period in the spring and summer and fall . The greatest bloom is usually observed in the early spring, with fruit and seed production starting in the summer and continuing until fall. Leaves are retained year to year. The California Live Oak (Agrifolia) has a long life span relative to most other plant species and a slow growth rate. At maturity, the typical California Live Oak (Agrifolia) will reach up to 70 feet high, with a maximum height at 20 years of 25 feet.

The California Live Oak (Agrifolia) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by bare root, container, seed. It has a slow ability to spread through seed production and the seedlings have high vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below 7°F. has medium tolerance to drought and restricted water conditions.

General Characteristics

General: Oak Family (Fagaceae). Coast live oak, an evergreen tree 10 to 25 m tall, has a broad, dense crown and widely spreading branches. The lower limbs of ungrazed trees often recline on the ground. Mature bark is gray and shallowly furrowed. Leaves are oblong to oval, 2 to 6 cm in length, cupped, with entire to toothed margins. The upper surface is strongly convex, deep green and smooth, but the lower surface is paler, with hairy-tufted vein axils. Like all oaks, coast live oak is monoecious and wind-pollinated. Acorn cups are composed of thin, flat scales. The one-seeded nuts are 2 to 4 cm long, narrowly conical, and mature in one year. On average, trees have high acorn production once every 2 to 3 years. Flowering takes place from February to April. Fruits mature between August and October.

Required Growing Conditions

Coast live oak occurs in the coast ranges from north central California southward to northern Baja California. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Cultivation and Care

Adaptation: It grows in well-drained soils on bluffs, gentle slopes, and canyons, and can be found up to 1400 m in elevation. This species is adapted to relatively warm, wet winters and dry summers moderated by fog and cool temperatures, but does not occur where the ground freezes. Although tolerant of various soil types, live oak prefers a deep loam. Common associates include species of sumac, lemonade berry, and toyon. Coast live oak is particularly well adapted to fire. Branches may produce new shoots after having been lightly burned. Trunks exposed to moderate fires often resprout from the base. Like most oaks, it has an obligate relationship with mycorrhizal fungi, which provide critical moisture and nutrients

Propagation by seeds: Oak seeds do not store well and consequently seeds should be planted soon after maturity. Nuts are considered ripe when they separate freely from the acorn cap and fall from the tree. Care should be taken to collect local fruits, because they may be adapted to local environmental conditions. Viable nuts are green to brown and have unblemished walls. Nuts with discoloration or sticky exudates, and small holes caused by insect larvae, should be discarded.

Propagation of coast live oak is highly successful by direct seeding at the beginning of winter. Once a site is chosen, prepare holes that are 10 inches in diameter and 4 to 5 inches deep. One gram of a slow-release fertilizer should be placed in the bottom and covered by a small amount of soil. Place 6 to 10 acorns in each hole at a depth of 1 to 2 inches. Temporary enclosures should be used to minimize herbivory by rodents or birds. A simple enclosure can be constructed from a 1 quart plastic dairy container with the bottom removed and a metal screen attached. Near the end of the first season, seedlings should be thinned to 2 or 3 per hole and to 1 seedling by the second season. Supplemental watering may be necessary if a drought of 6 weeks or more occurs during the spring.

Container Planting: Seeds may be planted in one-gallon containers, using well-drained potting soil that includes slow-release fertilizer. Tapered plastic planting tubes, with a volume of 10 cubic inches, also may be used. Seeds should be planted 1 to 2 inches deep and the soil kept moist. Seedlings should be transplanted as soon as the first true leaves mature. Planting holes should be at least twice as wide and deep as the container. Seedlings may require watering every 2 to 3 weeks during the first season. Care should be taken to weed and mulch around young plants until they are 6 to 10 inches tall.

General Upkeep and Control

Natural live oak regeneration from seeds tends to occur sporadically during winters with above average precipitation that falls evenly throughout the season. Seedlings are especially sensitive to trampling and too herbivory by rodents deer, and cattle. Common insects include moth larvae and tent caterpillars. Mature trees are especially susceptible to oak crown and root rot fungi (e.g., Inonotus, Ganoderma, and Laetiporus) which decay wood in trunks and roots. Activities that disturb or compact soil around trees, including construction and livestock grazing need to be avoided or carefully managed within the near the zone of leaf canopy. Summer irrigation near oaks should also be avoided, especially in urban landscapes, because it promotes oak root and crown rot. When desirable, mature trees consumed by fires may be allowed to recover from stump sprouts if replanting on large tracts is uneconomical.

Plant Basics
Category
Growth Rate Slow
General Type Tree, Shrub
Growth Period Spring, Summer, Fall
Growth Duration Perennial
Lifespan Long
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Early Spring
Displays Fall Colors No
Shape/Growth Form Single Crown
Drought Tolerance Medium
Shade Tolerance Intolerant
Height When Mature 70
Vegetative Spread None
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature 7
Soil Depth for Roots 36
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.5–7.5 pH
Precipitation Range 20–20 inches/yr
Planting Density 300–800 indiv./acre
Soil Textures Coarse, Medium
Soil Depth for Roots 36
Minimum Frost-Free Days 220 day(s)
Salinity Tolerance Low
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention Yes
Palatability Medium
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA