GARDENING : TROPICAL TREASURES MAKE WAY TO L.A.

Byline: Joshua Siskin

Leon Massoth, plant explorer and landscape designer extraordinaire, travels the tropical latitudes seeking rare treasures. His devoted clients eagerly await his return each time he ventures across the oceans. How do you measure devotion? One customer actually financed a recent expedition to New Guinea undertaken by Massoth.

He is the proprietor of Xotx-Tropico, 900 N. Fairfax Ave., West Hollywood; [phone]. For every 10 plants on display, nine are rarely seen, and of those nine, four or five are endangered species, the seeds of which Massoth personally collected during his travels.

``People from New York to Miami and from France, England and Germany have contacted us in search of rare plants,'' Massoth said, ``yet locally we are still, unfortunately, a well-kept secret. I want people to come in and buy our plants so that they can help in the protection and proliferation of endangered species.''

Massoth's interest in selling his plants is intimately connected with his desire to learn more about them. ``Since each garden microclimate is different from the next,'' he explained, ``only by growing a plant in many different situations can you gain a full understanding of its cultural requirements.''

There are several types of plants for which Massoth has a special fondness: hibiscuses, flowering vines and palms. In his very modest-sized nursery, it is hard to believe that he has more than 300 different species of palms. His hibiscus include a frilly crimson with matching red-tinted ruffled foliage and another wild species with red heart-shaped leaves reminiscent of the California redbud but with large yellow blossoms, both collected from Vanuatu in the South Pacific. He grows many true Hawaiian natives, including many subspecies of Hibiscus Arnottianus, known for their fragrant abundant white flowers.

As a Valley dweller, I was naturally curious about the cold hardiness of the plants in Massoth's mostly tropical collection. ``Many of these plants were gathered from mountainous areas,'' he informed me, ``and among their number are quite a few that will grow well in the Valley. I never sell a plant without carefully interviewing the customer as to the particular circumstances in which the plant will grow.''

At the entrance to the nursery, I noticed a tray of plants with shiny leaves that looked much like those of the gardenia. These turned out to be coffee plants, relatives of the gardenia, whose beans (seeds) had been transported to Los Angeles from Kona, Hawaii. But can you really grow coffee in Los Angeles? ``South of Mulholland, coffee can be grown without much difficulty,'' Massoth said, ``In the Valley, grow your coffee plants in the shade of a larger tree. Coffee cannot survive a hard frost, but it is always 5 to 8 degrees warmer under a tree than in the open air,'' he said.

Massoth grows trees and vines considered the most spectacular in the world, such as the flaming orange Colvillea racemosa, a tree from Madagascar, and Mucuna Bennettii, a scarlet wisterialike vine from New Guinea. An unusual ``self-sticking'' vine - it does not need help in climbing a wall or fence - that Massoth recommends for the Valley is Ampelopsis brevipedunculata ``Elegans,'' with pink, white and green variegated leaves that turn red in winter, and berries that change color from lilac to shocking blue.