Horticulture Notebook is a series of quick-reference articles focused on some of the favorite plants among Descanso’s staff and visitors. Each notebook page is a concise study of a plant and a guide to its location in the landscape.

Plant: Quercus agrifolia
(Coast Live Oak)
Size: 60' with canopy eventually arching down to ground.
Flowers: ?Inconspicuous catkins in the spring, followed by long, thin acorns in the fall.
Season: Evergreen
Provenance: ?Coastal foothill and plains from Mendocino County to Baja California
Location at Descanso: Garden wide

Quercus agrifolia (Coast Live Oak) is one of the most prevalent native California oaks, and the main resident at Descanso Gardens. More than 1,330 specimens grow within our fence line, with many hundreds more in the hills above us. The grey, gnarly limbs reach out, intertwine and support each other, forming the main tree canopy of the garden and giving this landscape its magical quality. The oaks cast their spell not only on us, but also on the camellias that thrive at their feet. A camellia plant is happiest in protection from direct sunlight and with an acid soil-both of which are provided by the oak leaf. The leaves provide shade while on the tree and, when they drop, form litter that decomposes slowly and releases acid into the soil.

Most of Descanso's oaks are about 130 years old, germinating after a great fire in 1880. A few grand specimens, now several hundred years old, survived. To see a couple of these old oaks visit the north end of the Rose Garden and the area adjacent to the Bird Observation Station.

Throughout the Gardens, the oaks you see today are the ones under which Manchester Boddy grazed cattle and developed a camellia plantation. Although oaks are known for strength and longevity, they are sensitive to activity around, and disturbance to, their root zones. These dry western natives are surprisingly shallow rooted. Adapted to a climate that receives very little rainfall, they look for moisture in the top layers of soil. This sensitivity is obscured by the fact that oaks often take many years to display signs of stress. Damage today may not express itself for a decade or two. This delayed reaction requires human stewards of the landscape to be vigilant with activities around the oaks.

The Coast Live Oak is green all year but dormant in summer when the climate is dry. Growth resumes in the fall. These trees often grow into monumental specimens and have special historic, aesthetic and ecological importance to California. Coast Live Oaks are subject to local protection by the County of Los Angeles under The Oak Tree Ordinance, which is administered by the Forestry Division of the County Fire Department.