GARDENING : LEMON VERBENA SURPRISES, PLEASES OBSERVANT VISITORS.

Byline: Joshua Siskin

Some plants should be in everybody's garden, and lemon verbena is one of them.

Lemon verbena is not a glamorous plant, and that is probably why everyone likes it; what one person considers gorgeous or glamorous - take bougainvillea, for instance - someone else considers garish, ostentatious or just plain boring. Also, it's one thing to be wowed by a plant when you first see it, or even drive by it on your daily commute, but something else entirely when you have to live with it.

The nearby presence of lemon verbena (Aloysia triphylla) will make the heart grow fonder of it each day. Invariably, this plant will end up in a corner of your garden, or off to the side, for lemon verbena insists on staying in the background. And yet, when relatives or friends come over, and you have all but finished the grand tour of your garden - when the roses have been suitably admired, the exotics from distant continents fawned over, the tomatoes tasted and the California natives given their due - you will stop in front of the lemon verbena and exclaim, ``Now here is something really special!'' You will then observe shrugging shoulders and perplexed expressions, for the plant contradicts common conceptions of botanical beauty. But then you will say, ``Pick a leaf, crush it between your fingers, and smell.'' In a moment, perplexity will turn to smiling appreciation and eyes will open wide. ``What is this plant?!'' your guests will enthusiastically inquire.

Olfactory experts generally agree that no plant has a more intense lemony fragrance than lemon verbena. Its crushed leaves exude a sweet lemon scent that could have escaped from Chanel's perfumery. Its leaves are regularly used in tea, as well as in flavoring cakes and for potpourri.

Lemon verbena (Aloysia triphylla) needs a bit more water than the average plant found in Los Angeles gardens. Although the Sunset Western Garden Book recommends planting it in full sun, Valley gardeners will economize on water, and not sacrifice much on growth, by planting it in half-day or slightly filtered sun. The only danger of reducing sunlight to this plant is that you make it more susceptible to aphids and whiteflies.

Lemon verbena has simple linear leaves that grow in whorls of three around its stems. It is a gangly shrub without a definite shape and may grow as tall as 10 feet. Its ornamental value is limited, partly owing to its semi-deciduous growth habit, which brings about leaf yellowing and some leaf drop during winter.

As with most herbs, the fragrance of its leaves is most intense when it flowers, which happens to be in late summer and fall. The flowers are white and pale violet and occur in large panicles on shoot terminals. Lemon verbena should be pruned sparingly.

Lemon verbena may be grown outdoors throughout Los Angeles but should not be used for landscapes in the Antelope Valley, where a cold winter could kill it. However, it makes a wonderful container specimen and is successfully grown indoors in a bright and airy room. It also does well on patios or balconies that receive a fair amount of sun. Soil should be well-drained to moderately water-retentive.

Speaking of lemon-scented plants, the lemon bottlebrush is currently in the midst of one of its extraordinary bloom periods. The lemon bottlebrush (Callistemon citrinus) is named for the musky citrus scent produced by its leaves and peeling bark, but it is far more famous for the brilliant scarlet bottlebrushes that adorn it each spring and fall. It is one of the first plants noticed by newcomers to this area and, although recommended for warm climates, does not flower as prolifically in wetter parts of the Sun Belt. It seems to appreciate a long, dry summer. One problem that some bottlebrushes experience is chlorosis (leaf-yellowing), which is a symptom of overly alkaline soil. Amend soil with peat moss prior to planting and spray leaves with iron chelate if chlorosis is visible on young trees. Unfortunately, it is difficult, if not impossible, to make chlorotic leaves green again on a mature tree.