GARDENING : WISH UPON A STAR FOR LOVELY `MOONBEAM' GROUND COVER.

Byline: Joshua Siskin

Among discerning Los Angeles gardeners, ``Moonbeam'' coreopsis could soon become enormously popular as a ground cover.

Generally, discerning gardeners are reluctant to plant ground covers. The success of ground covers - ivy, iceplant and gazania are the most popular types - often means the demise of a garden. While necessary to control erosion on slopes and useful for saving water and working as alternatives to a lawn, ground covers in a garden of flowering perennials are usually a disaster.

I never cease to marvel at the short-sightedness of the all-too-common decision to surround azaleas with ivy. As the ivy grows in, its strong roots squelch the growth of the more fragile roots of the azalea. At great pains, the ivy is kept from growing too close to the azaleas. Even so, the ivy will grow several inches thick while the azaleas stagnate. Invisible to the eye, the azalea roots are being strangled underground by the roots of the ivy. And then, one day, the azaleas begin to die, having grown but little from the moment they were placed in the ground.

Even where ground covers are planted in isolation from other plants, they are problematic. Purple rosea and red apple iceplants, for example, grow so fast and thick that they soon develop several inches of thatch, through which water cannot penetrate. As a result, these iceplants experience die back, in patches, and regularly require replacement planting.

It is because of such experiences that gardeners may roll their eyes when ground cover - any ground cover - is mentioned. Yet there are a few select species which, because of their non-invasive growth and ornamental attributes, deserve a second look.

Last fall, I planted two one-gallon containers of Coreopsis verticillata ``Moonbeam.'' This plant is captivating because of its unusual pale yellow flowers and thread leaf foliage. I had planted it before without success but was determined to make it grow this time. A raised bed of sandy topsoil and compost was prepared, and it was situated where it would receive no less than half-day sun. Yet the plants did nothing, refusing to put forth new leaves or flowers. I all but gave up hope when their leaves turned an unappealing reddish brown. Later, under stress of the severe cold we experienced, the plants virtually disappeared from view.

But suddenly, about six weeks ago, voila 

Growth was renewed and flowers started to appear. There has been no end to the parade of flowers and they should continue to form into the fall. It would appear that this ``Moonbeam'' coreopsis ground cover, like other common coreopsis species, goes through a period of winter rest, so do not despair when it goes into decline as the days shorten.

The pale yellow in the flowers of ``Moonbeam'' coreopsis is not frequently encountered in flowers. It is similar to the pale, sulfur yellow found in the yellow cultivar of the marguerite daisy (Chrysanthemum frutescens). It is a luminescent kind of yellow and so has aptly been named ``Moonbeam.'' It would nicely offset the vivid colors of red salvia and purple verbena in a flower garden. The plant has a modestly mounding growth habit and superficial roots.

I cannot vouch for the ability of this coreopsis to self-sow, although most coreopsis species do. Judging by its slowly spreading growth, it should readily propagate by division. It requires a scant amount of water but demands a faster-draining soil than the more common yellow-orange Coreopsis grandiflora.

The more I consider ``Moonbeam'' coreopsis, the more it reminds me of Geranium incanum, another favorite ground cover of mine. Geranium incanum also has soft, finely laced leaves and superficial roots. Growing to less than 1 foot in height, Geranium incanum self-sows with abandon but is easily deracinated if you should be bothered by where it travels in your garden. Its flowers possess the five overlapping petals of all true geraniums and, in this case, they are magenta rose in color. Usually, Geranium incanum is given exclusive ownership of a garden bed, but I have also seen it used as an underplanting with white ``Iceberg'' roses. Geranium incanum will need a moderate amount of water to look its best, although it can survive with a weekly soaking.

A last, lacy, garden-worthy ground cover, in my opinion, is chamomile (Chamaemelium nobile). Do not expect to walk away from this one, as it definitely requires moderately moist soil. Instead, walk over it. (Chamomile tolerates limited foot traffic). It will do best, in our hot valleys, in partial shade. The dried flowers make a fair tea, and the leaves are always pleasant scented.