GARDENING : MAT OF THATCH IN LAWN COMES FROM AFRICAN GRASSLAND.

Byline: Joshua Siskin

It's late on a Sunday morning and my sons, two of their friends and I decide to play baseball. We go to our favorite spot at the north end of Van Nuys - Sherman Oaks Park. To our astonishment, the place is mobbed.

The crowd is unexpected since, all summer long, we have virtually had this area to ourselves. But now it's September and suddenly jammed, even though we're the only ones interested in baseball. Everyone else has come to participate in a soccer league, and elegant silky uniforms are everywhere. Not to fear, though. We focus in on our favorite field and see that it is still available.

There are two fenced-in baseball fields at this end of the park. One is in excellent condition, but secured from potential players like ourselves by sturdy locks. The other, where we play, is open to all comers, but is usually empty, save for a few dogs running in circles, their owners shouting unheeded commands.

We've become accustomed to this field. It's the field that sees little baseball action, on account of a pothole in the middle of the pitcher's mound and other holes near first and second base. The field also lacks so-called curb appeal because of the uneven vegetative growth where evenly mowed lawns should be. However, we have no complaint. We know full well that were it in better condition, it would either be locked up and empty or open, as it is, but full of people.

The Kikuyu is a tribe in east Africa; kikuyu is also the name of an extraordinary, if underestimated, turf grass. An ancient saying of the Kikuyu people maintains that ``when elephants fight, it is the grass that suffers.'' I don't think elephants have been fighting in our favorite baseball field, but I do know that if kikuyu grass (Pennisetum clandestinum) had been planted here, it would have stood up admirably to baseball players, dogs and probably, if need be, elephants.

You hear a lot of prattle from certain people about plants not worth the effort because ``they're just too fussy,'' yet it is also true that when something is truly easy to grow, these same people are usually not interested in planting it. If it ``grows like a weed,'' if there's no challenge to it, the snob in many of us gardeners just won't allow it into our yards. This is certainly the case with kikuyu grass, the easiest of all grasses to grow.

Kikuyu grass is native to that unique African ecosystem known as grassland, which stretches from the margins of the tropics to the edge of the desert. Thus, it is found inhabiting areas with 30 inches of rainfall and areas with no more than 3 inches of rainfall, and everywhere in between. It is the ideal grass for Los Angeles, where the average rainfall is about 15 inches annually.

Most of us first encounter kikuyu as a ropy nuisance growing in our tall fescue (e.g. Marathon) or Bermuda grass. Initially, we will see this invader strictly as a weed. Over time, though, if we don't spray it out, it will eventually swallow up our fescue or Bermuda, and become our lawn.

Having a kikuyu lawn, however, is not anything to regret. It requires less water than fescue and less fertilizer than Bermuda to stay green. A big advantage with kikuyu is that weeds simply do not grow in it. Nor is it very susceptible to fungus problems or insect pests. Dogs are unable to damage it. Like all subtropical grasses, however, kikuyu builds a mat of thatch and may go dormant in winter, during which time it turns brown - unless it is dethatched at the proper moment.

A kikuyu lawn will need to be dethatched, in any event, at least once a year, so that water and fertilizer can penetrate to the roots. Based on the research of Jim Downer, a horticulture specialist for Ventura County, the best time to do this is around Halloween, at the end of next month. According to Jim Culley, a seed and turf expert from Stover Seed Co., the October dethatching - a procedure that slices through dead grass stems and roots - discourages the formation of rhizomes, which bring on dormancy. (Rhizomes are thickened underground stems which store carbohydrates in the manner of bulbs.) Without development of these rhizomes, the kikuyu will ``think'' it is still summer and continue to grow through the winter - barring a prolonged cold spell - and maintain its green color. Culley informed me that the fairways of some golf courses consist entirely of kikuyu.

Kikuyu is subject to ``scalping,'' if it is allowed to grow tall and then cut low. Culley says that keeping Kikuyu at a height of 2-1/2 inches will produce a lush lawn over time.

Since kikuyu grows so easily, it is not very easy to find if you want to make a lawn out of it. Seeds will be difficult to find, but stolons - above ground runners with roots attached - may be sold here and there. A simple way to find stolons would be to collect the lawn clippings from a public school or park in your neighborhood, where kikuyu has taken over. It is recognizable by its thick, ropey stems, which can be pulled out of the ground in foot-long, or longer, sections.

Tip of the week: If your plants are looking tired and worn from summer's heat, put off new planting for another two weeks. Take this time to turn the soil over and add compost or other amendments. October is the best month for planting all perennials, including trees, shrubs, vines, bulbs and ground covers. These plants may not show much growth until late winter or spring, even as their root systems develop underground. When the warm season returns, your fall-planted garden will be primed to grow.