GARDENING : Choosing the Right Tree Means Digging Up Background
Choosing a tree for the garden is not a matter of just showing up at the nursery on Saturday morning and hauling home the special of the day.
Trees form the bones of the landscape, add beauty and permanence, increase the value of property, shelter wildlife and help to counteract pollution; but every tree has its good and bad points. For success, a tree must be specifically suited to its new digs, and this takes research and thought on the gardener’s part.
The lavender blooms of the jacaranda, for example, are lovely on the tree and on the green grass to which they fall--but the tree does not belong anywhere near a swimming pool.
The gnarly trunk and weeping habit of the California pepper might lend a Spanish-hacienda look to the front yard, but plant it too near the house and the roots may end up unearthing the foundation.
Headed for the Pipes
The water-loving weeping willow is the ideal answer if a drainage problem exists on your property, but locate it near pipes, and the roots will make a beeline for them.
Frederick M. Braden, past president of the Southern California Horticultural Institute and the South Coast chapter of the California Native Plant Society, said that a bad choice--at least in the minds of many who live in the Palos Verdes area--is the planting by the original developers of Eucalyptus viminalis and E. citriodora .
Although they are stately and picturesque, they are “messy” (that is to say, they drop a lot of litter--leaves, bark, flowers, fruits, seeds), they are under attack by the eucalyptus borer, and they compete with other trees and shrubs for light and water.
Liquidambars are one of the few trees that give Southern California vivid fall color. In Torrance, says Braden, liquidambars planted along parkways are pushing up the concrete. While Braden is not in favor of their removal, he says, the area’s heavy adobe soil limits the fall leaf color to a monochromatic yellow. Liquidambars are also messy, dropping leaves and spiky seedpods.
A Daunting Search
In Southern California, there are hundreds of trees from which to choose, and the search for the right one for your yard can be daunting. Before the trip to the nursery, Braden says, the No. 1 question to ask is: “What will the tree be used for?” To add privacy or to screen an eyesore? To provide summer shade? To form a windbreak or to help muffle noise? To enhance the looks of a patio?
Other considerations having to do with the tree’s function and the care you want to invest will work to narrow your choices. Decide whether you prefer deciduous or evergreen. Deciduous trees drop their leaves in the fall, leaving the area beneath to receive light and warmth in the winter. In the summer they provide shade and coolness. But an evergreen is a constant presence.
The form, density and color are most important to consider. What kind of visual effect do you want to create? An Italian cypress stands sentrylike, while a ginkgo gives an airy, lacy look. The patterns of light and shadow that form beneath a tree are noteworthy aspects to landscape architects and designers.
Color of Foliage
Foliage color is chosen to complement architectural elements. For instance, the orange berries of a Queensland pittosporum or the rust-colored leaves of Southern magnolia bring out the hues of brick.
Some trees are chosen in part for their interesting trunks--young floss silk trees feature bright green, thorny trunks, for example.
Consider height at maturity, spread and the distance from the ground to the tree’s lowest branches (will you be able to walk and garden underneath?).
What kind of watering and pruning regimen are you willing to undertake? What is your soil like and how much room is there? Question what type of root system the site will accept. A tree with a far-reaching, shallow root system will be fine in a large area, but not near the curb. Some trees are susceptible to particular diseases or pests--Dutch elm disease, oak root rot, borers, for example.
Rate of Growth
Learn whether the tree in which you are interested is a fast or slow grower. Within a relatively short time, a fast-growing tree will reach its adult height. Of course, fast-growing trees are favored because of the natural impatience of most homeowners. But Braden advises limited use of fast-growing trees--such as eucalyptus, acacias, the silk oak, among many others--because they are generally short-lived and drop leaves more often (every six months or so; an oak might keep a leaf three to five years, Braden says).
However, “a planned option for the impatient,” he says, is to plant fast-growing trees among slow-growing ones; later the fast-growers can be removed (although this can be costly).
In a lecture and slide presentation at the South Coast Botanic Garden, Braden will talk about trees to choose (and not to choose) for Southern California gardens. Emphasis will be placed on trees that require little water. Topics covered will include how to select a tree and plant it, correct methods of pruning and shaping, feeding and watering. Specific questions from the audience will be answered.
“Trees: The Proper Selection and Care for Use in Southern California,” on Sept. 24 at 2 p.m., South Coast Botanic Garden, 26300 Crenshaw Blvd., Palos Verdes Peninsula; (213) 544-1948.
