GARDENING : BONSAI HELPS MAXIMIZE DWINDLING LANDSCAPE.

Byline: Joshua Siskin

For the longest time I've had a vision when stopped at the corner of De Soto Avenue and Oxnard Street, along that vast stretch of magnificently sloping land called Warner Ridge. I see a Valley version of the hanging gardens of Babylon - a wonder of the ancient world that was, in reality, a spectacular series of opulently landscaped terraces.

Rising one above the other, these terrace gardens contained exotic trees, vines and trailing plants that, due to their differences in elevation, appeared to be suspended in the air. Warner Ridge would have been perfect for this concept of garden design, except that Los Angeles, it would appear, is more like Babylon and less like a garden every day. Developers, you see, have nailed down the rights to turn Warner Ridge into a shopping center, not into a garden or a park.

Not to worry. We may be running out of open spaces in Los Angeles, but there is, perhaps, a way out of this dilemma. It's known as bonsai, a whole landscape of which can fit on the top of small table. Some may question whether tiny horticultural contortions can satisfy our longing for lush landscapes and expansive gardens. But who knows? The day soon may be upon us when no more space for gardens will be allotted and we will have no choice but to grow everything in little pots.

The Bonsai Survival Manual (Storey Publishing; $21.95), by Colin Lewis, thus appears to have arrived in the nick of time, even if the art of bonsai is 2,000 years old. Bonsai's originators, noblemen of the Han Dynasty in China, did not allow anyone of inferior birth to indulge in bonsai, since ``it was regarded as too spiritually enriching for the masses.'' One Chinese emperor, who constructed a miniature model of his empire (so he could see it all at one glance), complete with bonsai landscape, is said to have put to death anyone who owned a bonsai, since this represented a threat to imperial authority.

When China invaded Japan in the 14th century, much of Chinese culture was introduced to Japan as well. This culture included bonsai. Actually, the word bonsai is Japanese; ``bon'' means tree and ``sai'' means dish, tray or pot. The Japanese refined the art of growing miniature trees and took it in directions undreamed of by its Chinese practitioners, whose sole intent was to create small-scale, realistic models of trees. The Japanese began to focus on plants with interesting flowers or variegated leaves as well.

Yet bonsai, as we know it today, with its many different defined styles, actually was not developed until the 1800s in Japan. Omiya Bonsai Village, which contains the greatest bonsai nurseries in the world, is located outside Tokyo and was founded by bonsai masters. GIs returning from Japan, after World War II, brought samples from this village and soon after, with the encouragement of Japanese-Americans, popularized bonsai in the United States.

Bonsai usually are grown outdoors, although, according to Colin Lewis, they may be grown indoors as well. The problem is acclimatization. If you acquire a bonsai that has been raised outdoors and immediately start caring for it as an indoor plant, it soon may die. Bring the plant indoors for an hour or two the first day and lengthen the time the plant stays there, until it has adjusted fully to its new surroundings.

The best exposure for a bonsai, whether grown outdoors or indoors, is bright light - which does not mean intense sun that quickly can dry out soil and burn the tips of leaves. Lewis' advice on fertilization of bonsai trees, could be applied to all plants growing in containers: ``Only feed when in active growth; don't feed for three weeks after repotting; stop feeding deciduous trees before the leaves turn to a fall color.

The soil mix for bonsai should contain peat moss or leaf mold and washed sand, the proportions, depending on the type of plant that is grown; through sifting, soil particles smaller than 1/16 of an inch and larger than 1/4 of an inch should be removed.

Deciduous trees should be repotted just before dormancy ends in late winter. Tropical and subtropical trees should be repotted in midspring; azaleas should be repotted as soon as they finish flowering.

Lewis provides detailed instructions for growing 50 species of plants in the bonsai mode. Many of these will be familiar to Los Angeles gardeners, including: sago palm, Japanese maple, bougainvillea, bamboo, cotoneaster, jade plant, Ficus benjamina and Ficus nitida, fuchsia, ginkgo, crepe myrtle, common myrtle, orange jasmine (Murraya), Nandina domestica, olive, Japanese black pine, Podocarpus macrophyllus, pomegranate, pyracantha, azalea, Chinese elm and wisteria.

Tip of the week: The best way to get rid of running bamboo, such as golden bamboo (Phyllostachys aureus), is to physically dig it out. Its roots and rhizomes are not deep, but their removal requires considerable elbow grease. Such bamboo never should be allowed into a garden, although it can make an attractive container plant. Clumping bamboos are less aggressive and may be planted in the garden without chaotic result.