Where's the best place to plant a redwood? The name is a big clue: Coast Redwood.
Redwood trees are planted everywhere and subjected to lots of abuse, but they are survivors. I've seen them growing in parking lots, as sheared globes, and as tall screens, all of which are bad ideas. Often they're chosen because they grow fast and, after all, they are the state tree of California.
But if you look closely, most of the redwoods planted as single trees outside the fog belt are not healthy, with dry branches or sparse foliage. If they're mostly green, other shrubs and trees planted nearby may have a harder time surviving, both because of the heavy leaf drop and because the redwoods greedily take all the water they can get.
Many trees require some regular water to get established in the first couple years, but then are fairly drought tolerant. Redwoods need a lifetime supply of ample water.
If you already have a redwood and it's doing well, make sure it's getting enough water.
According to arborist Barrie Coate, a redwood tree needs 20 gallons of water per inch of trunk every month. So a 12-inch-diameter tree would require 240 gallons of water a month to stay healthy. If you're not watering the redwood enough directly but a vegetable garden or lawn is nearby, the redwood's roots will grow toward the regular supply of water.
Birch trees are the only other trees that require as much water as redwoods, Coate says.
Not surprisingly, redwood trees are native to the coast ranges, not to inland valleys. In the coast ranges, redwoods don't need to be irrigated because they get all the water they need from fog drip. My favorite place to be on a hot summer day is in a coast-range redwood grove.
Unless you can meet the world's tallest tree's increasing need for water as it ages, you're better off planting a different tree.
Coate, with 40 years of experience as an arborist, says the following trees have good form and are well adapted to gardens.
Big-leaf maple: a fast-growing tree with good fall color that is native to Santa Clara County.
Santa Catalina Island mountain mahogany: a small fast-growing tree, with better form than the mainland species.
Coast live oak: noninvasive roots and a good choice for a drought-tolerant hedge, reminiscent of beech hedges grown in England. Planted in a grove, each tree must be 40 feet from its neighbors to develop a good canopy. Though oaks are sometimes regarded as slow-growing, Coate says a coast live oak or island oak can grow 2 feet a year if a vigorous specimen is chosen.
Canyon live oak, scrub oak, and leather oak: slower-growing, nicely shaped smaller oaks.
Valley oak: not susceptible to sudden oak death; must be professionally pruned when young to ensure good structure.
California buckeye: a wonderful tree with silvery stems, an awkward youth, and a tolerance for irrigation.
© 2007 Tanya Kucak