IN THE GARDEN TAKE ADVANTAGE OF MAY GROWTH SPURT.

Byline: JOSHUA SISKIN

In Los Angeles, plants grow faster in May than in any other month.

In May, the lengthening days and warming nights push plants to grow at a rapid pace that continues through most of June. Then, the scorching temperatures of July, August and most of September curtail plants' rate of growth until, at last, mild October arrives, encouraging a final spike of growth that stops abruptly in mid-November.

You can take advantage of plants' powerful growth this time of year by rejuvenating raggedy specimens, especially those that respond favorably to radical pruning. Some plants exhibit thicketlike growth. The more you cut them back, the more they prosper and spread. Plants in the barberry family, such as nandina and mahonia, come to mind, as do rhizomatous or bulbous perennials such as daylily and society garlic.

Mexican lobelia 

Take a look at Mexican lobelia (Lobelia laxiflora). Among experienced gardeners, the word lobelia (lo-BEE-lee-a) conjures up demure mounds of marine blue flowers (Lobelia erinus), the perfect edging plant. Mexican lobelia, however, has orange-red tubular blooms and must be given its own space. It sips a minimum of water in partial sun as it sprawls in every direction. Cut it back hard this time of year and it will grow back quickly and bloom until winter.

African bulbine

In the manner of Mexican lobelia, African bulbine spreads by rhizomes in semi-dry garden spots. African bulbine (Bulbine frutescens) is nearly always in bloom and bears either butter-yellow or orange-and-yellow star-shaped flowers. Its slender leaves are succulent and, when broken, exude gelatinous sap, which, like that of aloe species, is used topically in the treatment of sunburns and rashes. If you have a eucalyptus tree under which nothing will grow, plant African bulbine there and watch it thrive.

Mexican lobelia and African bulbine appear on a list of plants, suitable for the high desert, that has been compiled by El Nativo Nursery (www.elnativogrowers.com). If you live in the horitculturally challenged Antelope Valley, you may want to take a look at it.

Yarrow and fuchsia

Yarrow (Achillea millefolium), a spreading ground cover with lacy foliage and lace-cap flowers, appears on this list of water-wise and cold-hardy species, as does the California fuchsia (Zauschneria californica).

California fuchsia (few-sha) is one of those plants that none of our gardens should be without. It grows effortlessly with a scant amount of water and has a strong self-sowing tendency so that it may start popping up in unexpected places. Its flowers, which appear in the red-to-orange spectrum as summer begins, are attractive to hummingbirds.

Butterfly bushes (Buddleia species) are also recommended for the high desert. They put on a tremendous amount of growth each year and may also be cut back hard in early spring to keep them more or less compact. Their long flower wands in pink, mauve, purple or white act as magnets for butterflies of every description.

Q: About 15 years ago I planted lavender star flower (Grewia caffra) at the back of my lot as a screen. They flourished, but last year, one by one, the leaves started to wilt and the plants collapsed. I thought perhaps the drought last summer had stressed them so I watered the remaining ones but the last one has now shown the same symptoms. Do you know what might be causing this? I noticed a plant a few blocks away that seemed to have the same symptoms.

-- David Garcia,

Sherman Oaks

A: Lavender star flower has captivating, 10-petaled flowers and decorous, serrated foliage. It is used as a hedge, growing up to 10 feet, and as an espalier plant against a fence. It is subtropical, however, and short-lived in our dry climate. You should be pleased to have had it for 15 years -- it typically dies sooner than that.