IN THE GARDEN TRELLIS GARDENING ADDS NEW LOOK TO ANY AREA.

Byline: JOSHUA SISKIN

If you have limited gardening space, you really should consider going vertical. And even if you have enough room to grow whatever you want, you are still entitled to experiment with and experience the benefits of vertical gardening.

Vertical gardening means growing on trellises. A trellis takes up little ground space but can provide many square feet of growth up in the air. Trellises are not only practical for maximizing gardening space, they can also add beauty, warmth and excitement to bland block walls, staid pool decks and boring shrub beds. The most obvious candidates for growing on trellises are vines.

Anyone with a filtered sun exposure should try clematis, an underutilized species with magnificent blue, pink or white flowers that will grow in the Valley when conditions are right. Make sure the roots of clematis are protected by surrounding plants and/or mulch. The ideal setting for clematis is an established shrub bed. If you can squeeze a clematis in between two shrubs, its roots will be properly sheltered as it winds its way up toward the light.

Other flowering vines for trellises include star jasmine, glory bower (Pandorea), lavender trumpet vine (Clytostigma), blood red trumpet vine (Distictis buccinatoria), yellow Carolina jessamine (Gelsemium), passion flower (Passiflora) as well as climbing roses and bougainvillea.

Actually, any trailing ground cover and virtually any shrub or tree with pliable stems can be trained to grow up a trellis. I have seen ivy geranium, prostrate rosemary, gazania, lantana, princess flower, camellia, gardenia, calliandra, russellia, pyracantha, loquat and even magnolia growing on trellises.

Q: I have two tropical hibiscus, both infested with whiteflies. How do you get rid of them? I have a guava tree in one corner of my yard

that produces heavy shade; impatiens won't even grow there. I don't know if the problem is lack of sun or interfering tree roots. What would you suggest planting there?

- Susan Schless,

Northridge

A: I suggest radical pruning of whitefly-infested plants, then regular hosing down of leaves and ample fertilization. I have heard that spreading earthworm castings around the base of a susceptible plant helps deter whiteflies, but I have no personal experience with this procedure. Small trees such as guavas and bottlebrushes produce heavy shade under which no plant can grow. I suggest spreading cedar mulch under your tree rather than struggling with sun-starved ground cover or bedding plants.

TIP OF THE WEEK: Growing plants on trellises is an ideal way of making the most of patio or balcony space. Use the largest containers you can accommodate and make sure you get at least four hours of full sun daily.