THE following four plants should be in every garden in Washington: Photinia serrulata, Nandina domestica, Mahonia bealeii , and the Kurume azalea.

The azalea, at least is everywhere, and is so common that snobs now complain of it; especially are they sick and tired of "Hinodegiri," "Snow" and "Coral Bells," they keep saying.

Which is all very well for snobs, but they are priceless plants all the same. In fact, true gardeners are easily separated from precious fools by the Kurume azaleas. Plantsmen know them to be treasures while fools dislike them because they are common.

But what of the other three broadleaf evergreens, which should be as common as the azalea. Where are they? It is astounding that many gardners seem to be unfamiliar with them, and this is a scandal.

The Photinia grows with reasonable slowness (like a holy) to perhaps 8 or 10 feet. Left to its own devices -- and a plant so aristocractic really should not be fiddled with -- it makes a globe of black-green to olive-green, with high lights of bronze.

The individual leaves are leathery, not quite as long as your out-stretched hand, rather oval, with noticeable saw-teeth along the edges.

The maturity there are blooms somewhat like an elder's, followed by dull red berries in great clusters. But ordinary mortals should not expect flowers and fruit -- it is too much to ask or expect -- and while they are pleasant enough, neither flowers nor fruit justify planting the photinia. But the leaves alone do justify giving this shrub a place of honor.Against a house wall, where there is a dull expanse of 10 feet of brick say, the photinia is beautiful.

But since it does not require wall protection, I would not give it the valuable shelter of a wall. It does prefectly well in the open. At the end of a garden border or beyond a shady fish pool, or in front of a garage, or anywhere in light woodland, it is perfect.

It is beautiful at all seasons. I like it best in late March or early April when its new growth sprouts forth in sheaves of waxy red-bronze. As a background for daffodils it is without a superior.

It should be planted outdoors in the spring, from containers or else balled and burplapped.

Equal to it, with a very different beauty, is the nandina.

The Chinese plant it near their houses, and so do the Japanese. It is said the twin twigs of the nandina make flawless toothpicks, and while I think toothpicks are disgusting, I mention this valuable feature of the plant for those of my friends who happen to be vulgarians.

Assuming that many, however, are not forever digging about their molars, the nandina is still a practical plant. It has no ugly season, but is exciting in fall, when its much divided leaves, like a ferny bamboo turn bronze with touches of crimson or scarlet to contrast with the basic green. In winter this color holds, and there are fat pyramidal clusters (the size of a crape myrtle bloom cluster) of scarlet waxy berries.

In spring, the new leaves are buffy-salmon-bronze, promptly turning green, a fine neat medium green. The foilage arches out and droops down a bit. The plant sends up numerous stems, so the effect is that of a chest-high bamboo.

It likes good treatment, with medium soil (the sort we provide without doing anything) with rotted manure as top dressing from time to time. If the plant ever gets too tall and leggy, just cut the tall stems down, and new ones bush up from the ground.

Sometimes people have "picture windows" in their houses, and they can be made a little less ridiculous, a little less ugly, by planting the nandina in stout clumps at the ends. They provide something worth looking at, for a change.

In winter the cardinals, probably for exhibitionist reasons, often sit in the nandinas. I suppose they eat the beries. In any case, the nandina in unique for its feathery or ferny look all winter. It makes a good unclipped hedge, by the way. And sometimes the gardner would like a dense clump of green at the corner of a lot.

Something not too forbidding or furnereal, and the nandina is flawless for such a purpose.

It should be among the commonest of garden plants, and it is beyond all understanding why it is not. Some day it will be solid in Washington, and my ghost, in that day will be pleased to have had a part in banging gardeners over the head to plant it.

The mahonias are all beautiful, but I mention only M. bealeii, which (like all the others) has leathery evergreen leaves that color here and there with crimson, bronze and so in the winter if the plant gets sun, but otherwise stays a medium-deep green leaning towards olive.

Like the nandina, it makes nummerous stems, and grows up to about 6 feet. Like the nandina it is easily cut down if it gets leggy, thus allowing new growth from the bottom.

It has spies of yellow flowers, vaguely like the lily of the valley, in the center of its terminal rosettes of leaves. These start to open in December and bloom off and on until March.

The are followed by large clusters of blue berries with a bloom on them like grapes or plums.

How often in Washington you find a little square of land outside the living room window, maybe 25 feet square. Usually this is sacred to dust and a ratty half-dead Norway maple.

If the maple is joyously sawed down, and the tiny space enclosed and planted with the shrubs mentioned here, it will for an ever-loving change give you some active pleasure.

If a tree is thought desirable, obviously a Washington Thorn or Sargent's crabapple, or a dogwood, etc. will be better than one of those wretched maples that belong in the middle of a deep forest.

The tallish photinia is perfect as a screen. A litlle thicket of nandinas, a fat clump or mahonias, and maybe a drift of Kurume azaleas (you could, after all, try 'Pink Pearl,' whihch is the loveliest of them) would be all anyone could ask.

If the center of the land were kept open, it could be planted with grass.

There might be a shallow pool for birds to drink from. Or instead of grass (if you didn't intend to walk there, but only to view it from the house) such substitutes as lily-turf or bugle-weed or barren-wort.

Such a lille plot would look beautifully dressed at every season; handsome in winter snow and ice as on the most sweltering day of July.

No spraying would ever be necessary. A bit of cow manure every other fall would be appreciated but not strictly required.

T is conceivable, I guess, that someone could be found who did not admire the plants mentioned today.

In towns like Memphis or Atlanta these plants are everywhere. Do not suppose they are uncommon here because they are too tender -- a thing you could conceivably hear said by an ignorant man.

They are perfectly and unarguably hardy in Washington.

I think maybe our garden designers come from the Arctic along with our nurserymen. There is not other explanation.