AT HOME : Trees Worth Coddling : Experts advise not to water anywhere near the oak in summer or plant grass under the canopy. Be judicious with pruning.
Before the Spanish arrived to clear the land for vineyards and missions, long before the settlers and developers started plowing up the landscape, oaks covered the San Fernando Valley and its surrounding hills. They gave shape and substance to the terrain and provided food and shelter to generations of humans and small animals. A 700-year-old oak in the West Valley fed Indians 200 years before Columbus, and the same tree shades us today.
There are 18 oak species in California--nine trees and nine low-growing plants, but only two oak trees are common in the Valley, both evergreens: coast live oak ( Quercus acerifolia ) and interior live oak ( Quercus wislizenii ). They are not easy to tell apart: Both have small, leathery dark green leaves (coast oaks are more holly-like; interiors have smoother edges), spreading branches, dark, rough bark and skinny acorns about an inch long. The leaves of the coast live oak don’t form a dense canopy; it’s possible to sit in the shade under a coast live oak and watch the sun through its branches.
A homeowner with an oak tree is rich. A mature, spreading, shady oak can add thousands of dollars to a property’s value and priceless pleasure to a homeowner’s well-being.
“One of the reasons we bought our house is for the oak in the front yard,” said Lisa Rasgon. A large, low branch of Rasgon’s coast live oak spreads across the front of their Encino yard, at once a barrier and an invitation. “We love the way it embraces the house. It’s really an unusual tree.”
But while old oaks are a joy to behold, some can be hell to maintain. Their roots are susceptible to oak root fungus, and once the disease gains a foothold, the tree’s death is inevitable.
To prevent the fungus from attacking in the first place, never, ever water inside the tree’s drip line; to be completely safe, don’t water anywhere near the tree in the summer. Never put a live oak in a lawn.
Oak branches can be brittle; when a branch from a large old tree falls, it can make an expensive dent in a house or a car. Many homeowners have their oaks trimmed often to prevent crashing branches.
The Rasgons hire a bonded tree service to trim their oak annually, at a cost of about $2,300. It’s possible to get away with trimming less often--I know one woman who had a large oak in her back yard and never trimmed it in the 12 years she lived there. Never watered it, either. That tree is still alive and healthy, but it may just be lucky.
At Orcutt Ranch and Horticultural Center in West Hills, the 300-year-old oaks are trimmed infrequently--about once every four years--by certified arborists. Anyone with a really fine specimen oak, especially one more than 100 years old, should not take too many chances. Old oaks are irreplaceable: Coddle them.
Nine species of oaks grow at the Theodore Payne Foundation in Sun Valley, and several ancient coast live oaks can be seen along Orcutt’s nature trail in West Hills. The 700-year-old giant is on the edge of the ranch, visible from the nature trail.
“Oaks of California,” a beautiful book by Bruce M. Pavlik, Pamela C. Muick, Sharon Johnson and Marjorie Popper (published by Cachuma Press), is an excellent source of oak lore and history.
Where and When Location: Orcutt Ranch and Horticultural Center, 23555 Justice St., West Hills. Hours: 8 a.m. to 5 p.m. daily. Call: (818) 883-8531.
