THE MOUNTAIN laurel is almost never seen in new small gardens, probably because it grows slowly and therefore costs more than most broadleaf evergreens.

But I noticed a batch on sale at a garden center in Northern Virginia and boughtone, hoping that in time it will bloom and remind me of those wonderful laurel thickets of the Blue Ridge.

They are called "laurel hells," and they are indeed hell to hike through, though in gardens, alas, they never flourish in barrier type thickets.

Kalmia latifolia has always been one of the most admired of American plants, rivaling the camelia, the stewartia, the magnolia in quality and surpassing all of them in floral effect.

The leaves are polished and commonly discolor during winter to various combinations of bronze and green, sometimes with a bit of dead black and brown. The plant always looks wild, open, gnarled, windswept.

It is happiest on a slope, it abhors sticky wet soil; it flourishes with endless rain and a leafy soil. It likes to run its roots near the surface, which should be mulched with oak leaves.

The flowers are blush-white, verging to red in the centers. Like little pinks in clusters or half-domes, they bloom in late May and June. There seems to be a fondness nowadays for deep pink and red kalmias, but the handsomest is the ordinary blush-white wild sort.

Breeders ought always to cross flowers and raise seedings, but the truth is that it is rather hard to improve on wild flowers as far as beauty is concerned.

The mountain laurel does not care to be moved about. Unlike azaleas (which endure repeated shifts of site, which is possibly why women admire them so much), the mountain laurel does not move easily. Usually when they dig it from the wild, they saw it down to a foot in height (it may have been six or seven-feet tall) and hope for the best. Usually it shoots up strongly and within a few years is full of flowering stems.

I gave mine a couple of buckets of sopping peat moss, though leaf mould would have been better, and a site on a steep slope.

In drought, or even in dry spells such as we had this summer, it is a great pain to have a number of plants on a slope, since they dry out and have to be watered. This is especiallythe case if they have been moved within the past two years.

On the other hand, many plants really do better on slopes than on the level. In heavy soils, such as most of us have, you will notice camellias, yews, box, pieris, azaleas, flourish madly on slopes that are kept reasonably moist. Ordinarily there is no need to water such plants once they are established, but during a drought, watch out.

Azaleas, which are typical woodland plants with shallow root systems and fine hair-like roots, will not stand clay on the level, but on a slop the soil can be as heavy and sticky as it likes, provided there is a layer of rotting leaves at the top and provided it rains all the time (as it does here, God knows).

I have seen yews looking sad and unhealthy from no other cause than waterlogging. Often yews start out with a flourish, then begin to waste away as their root systems penetrate deeper. On slopes they never die.

A few years ago I moved some small yews that had been planted beneath windows before I bought the house. They would have blocked the light considerably. They grow about a foot a year -- they are perhaps 10 feet high or so now -- and I wanted them along a walk in the back.

Two of them are planted where steps cause a drop in level. The third one, near an alley gate, is on flat land. The two planted at the edge of a drop have grown twice as full as the other one, and are far more flourishing and hearty.

Gardeners fond of pictures may have noticed the superb yews at Powys Castle, some centuries old -- all of them growing on a virtual cliff.

I mention this to emphasize the importance of good drainage for plants, especially the ones mentioned, and also to urge making use of slopes and drops in level even in small town gardens. It is a pity to flatten everything out like a tennis court, when so many plants prefer the original roughness.