Friends of the Garden
Plant of the Month
July 2012
Quercus agrifolia (Coast Live Oak)
Light: Sun but can take a touch of shade
Soil: Likes fair to good draining soils but can do well in clay.
Water: Infrequent to drought tolerant
Perhaps this wonderful tree is prettier when the rains wash the leaves a glossy dark green in the winter. It is certainly lovely when cloaked with dropping little catkins of flowers and new pinkish new growth in the spring. But it is in summer that this noble tree shows how tough it is despite heat and drought.
Coast live oak occurs in a Mediterranean climate characterized by mild, wet winters and hot, dry summers and is native to California and Baja. When you see spreading oak trees in our hills and canyons throughout wild Orange County it is this Oak you are most likely seeing. The beautiful oil paintings of early California done by Granville Redman and William Wendt showing golden hillsides cloaked with majestic dark green trees were studies of these majestic Oaks. (Not as well known as those works of art-the GWC Native Garden logo designed by Bill Atkins features a young Coast Live Oak.)
Coast live oak stands are typically from 40 to 110 years old, and individual trees may live over 250 years, ranging in height from 20 to 70 feet and about as wide. Trunk diameter can range from a modest 1 foot to 4 feet in really old specimens. The bark of young trees is smooth but with age it develops furrows, ridges, and a thick bark. The tree’s crowns are broad and dense, with foliage often reaching the ground in the wild (unless grazed by livestock or deer). In gardens we normally lift the lower branches to be able to see its lovely branch structure and to have a place to sit on a hot summer day! Acorns normally form in the late summer and were once a major food source to the indigenous California tribes who leached the tannins from the acorns and made flour from it.
Obviously this tree would be too large for small yards, but in larger landscapes I used to wonder why they were not used much. When the recent re-landscaping of the 5 and 22 freeways occurred there were many other trees installed but none of these beauties. What a lost opportunity to bring back some of the character and beauty of orange county that has been lost over the years of development. Happily now they are used more frequently in park and larger community gardens, in fact at GWC the design at the LRC building has a row of them on the north side of the building.
They are not as slow growing as some fear and granted, they are not a showy flowering tree, but what great structure! If you plant anything under it make sure it is not something needing heavy summer water, since they generally do not like to have wet roots during warm weather-that combination or warm soils and water can promote root rot in the Coast Live Oak. Otherwise they are as easy to care for as most tree species, native or exotic, planted in southern California. If you would like to see one that was planted in 1975 simply visit the center area of the garden at GWC. Spend some time looking up into its canopy of holly like leaves-It is a serene and beautiful scene.