GARDENING : WHILE MANY WISH IT GONE, SPURGE HAS ITS FANS.

Byline: Joshua Siskin

The sun-loving equivalent of baby's tears, it grows rampantly and, left unchecked, will take over every bare spot of garden earth within a week or two.

Spotted prostrate spurge takes over just when you have declared victory over petty spurge (Euphorbia peplus), its cool-weather cousin. Petty spurge is also about as delightful as a weed can be. Its claim to fame is a fresh yellow-green color and an unusual leaf arrangement that gives it the look of a diminutive pagoda.

Like all plants in the Euphorbiaceae or spurge family, these weeds have a milky white sap that can cause severe skin irritation to certain people in much the same way that different people will be variously affected by contact with poison ivy. Hortus Third advises against planting the various ornamentals in the spurge family near ponds, since sap from their broken roots can be lethal to fish. The juice from certain spurges has been used in making poison arrows.

The castor bean (Ricinus communis), another spurge relation, and considered by some to be the most poisonous of all plants, is a common weed in Los Angeles vacant lots and other open spaces. It is a striking species, growing up to 15 feet tall, with sharply lobed, palmate leaves that turn bright red or crimson as the season progresses. Despite its onerous reputation, many interesting cultivars of castor bean have been developed, although they are seldom available commercially.

Also in the spurge family is the Chinese tallow tree (Sapium sebiferum), one of the most desirable of small- to medium-size ornamental trees. In my humble opinion, it deserves equal billing with the crepe myrtle as a street tree for our city. It has leaves that shimmer in red, bronze and gold during the fall. Unfortunately, it is virtually ignored in Los Angeles when tree-planting decisions are made.

It was in the Mediterranean seacoast town of Netanya, Israel, that I made the acquaintance of the snowbush (Breynia nivosa), an extraordinary tropical spurge with variegated green, cream and pink leaves. It is used as a hedge plant in Netanya, although I don't believe it would grow in Los Angeles, except as a house plant, because of our low humidity and cool evenings.

Another tropical hedge plant - it's a staple in the Cayman Islands - that we grow as a houseplant is the croton (Codiaeum variegatum), also a spurge. The croton is that plant whose waxy, variegated leaves are colored in bright green, yellow and red. It needs good light to show its colors, so make sure you put it either next to a window or below a skylight.

The name game

Two weeks ago, I asked two questions in this column and was lucky to have readers who could answer them. The first concerned the proper name of an oxalis with maroon leaves and lilac flowers.

I was informed by Alan Pollack that the full botanical name of this plant is Oxalis Regnellii ``Rubra.'' Ted Rupp passed along similar information, together with the plant's common name, which is pink shamrock. Rupp also wrote that ``despite my notorious brown thumb, I have six plants still growing from bulbs purchased in 1993.'' Rupp bought these from Mellinger's, a mail-order nursery (2310 S. Range Road, North Lima, Ohio 44452; [phone].

Lettuce enlighten you

I also wondered why lettuce grown in Los Angeles gardens tastes so bitter. I was enlightened by Theodora Howell of West Hills, who is horticulture chair of the West Valley Garden Club, which is as wise a group of gardeners as you will find anywhere.

Howell wrote as follows: ``Being from the Midwest, I can assure you that lettuces belong in cooler weather. When the weather gets hot, it turns bitter and `bolts,' which means it's going to bloom and set seed. We buy lettuce 12 months of the year because of air conditioning and greenhouses. But in the home garden, it simply cannot be done. Sow lettuce in batches, starting in October. The batches should be sown two weeks apart. One package of seeds can make three or four batches. Then when you harvest, and you can start as soon as there are good-sized leaves, all you do is pinch the leaves from the plant instead of uprooting it. That should keep you in lettuce (all kinds) until June, if the weather stays cool. Don't even think of growing lettuce in the hot weather we have had so much of this year ... But I wonder why the nurseries even sell lettuces in six packs when it comes up so quickly and easily from seed.

Tip of the week: Yvonne Savio and her master gardeners impart this bit of advice: ``Use pliers to pull unwanted tree seedlings without having them break off at ground level and grow back stronger than ever. Grasp the stem at the soil line, carefully wind the stem around the pliers, and pull straight upward. The whole root system will come out, even in dry soil. Soaking the area the day or two beforehand will ease the task.''