MARIGOLDS are bright and beautiful if, like cousins, you don't have too many of them at once.

Hardly any flower makes sense when bedded by the thousand, though that is the way you commonly see flowers used in parks. Nobody expects much imagination or thought in public plantings, however; and the theory -- as I understand it -- is that if you're driving along at 70 miles an hour, it makes no great difference what the flowers are or how they are grouped.

But in home gardens, needless to say, there is no reason to mass flowers of the same kind endlessly -- there is no reason to have solid beds or (here I commence to meddle) for that matter solid edgings of a single brassy flower. iThe mere fact that you get a lot of seeds in a packet doesn't mean you have to plant all of them. They keep quite nicely for next year. A handful of marigolds, stuck in here and there among violet or blue or yellow petunias, can be festive, whereas a solid mass of marigolds, apart from being overwhelming, looks dull.

It is the principle of the skyrocket, of course, that applies here. Rockets seize all eyes when they burst in gold rain against a dark sky. But if you make the sky solid with gold (as the sun does at noon) then you rather lose the effect of skyrockets. Similarly, a touch of scarlet is one thing in a necktie, but something else again when shirt, pants, socks, shoes are all vermilion.

Without further laboring the point, therefore, let me respectfully command you to plant your marigolds for brilliant accents, not for masses.

It is never a question that some particular way of using color is "right" and other ways are "wrong." Rather it is a fact that drama and delight are lost by using colors some ways, and enchanced by other ways. Now I have a friend who would be happy if all the world were turned purple, and that person actively dislikes all yellows. Strange. But then people are. And who would wish to argue with somebody strangely constituted colorwise? Such persons should go right ahead with color arrangements that please them, however odd.

But relatively normal gardeners usually respond with the greatest pleasure when colors are used not necessarily sparingly, but rather carefully.

In general, the more brilliant the color the less of it you need. Or put another way, the more brilliant it is, the sooner you have a belly full of it.

This does not mean (as the timid suppose) that the garden should have nothing buy gray and puce in it. Quiet colors can be notably boring. I have a gang of dark violet petunias in pots. When I group these all together they are fairly dull, however safe from the reproach of vulgarity. Of course all gardeners worth their salt soon learn to stop thinking in such terms and start thinking in terms of what gives delight, vulgar or not.

But these dark petunias are wonderfully alive if two pots of raw brilliant pink petunias are stuck in among them. The pink is assertive and loud and restless, but when used sparingly with dark purple it is magical and splendid.

Among roses you can hardly help noticing that whole family of neon-electric vermilion-orange-pink. There is nothing wrong with the color as a color -- it is clear, brilliant, sparkling, and if it makes you rather sick it is because too much of it is used. If there is a paved walk in the garden, it is possible to set up poles near the end of it, covered with vines, a shady bower with the walk continuing through it. If there is a garage, as there often is at the back of a garden, try covering the walk with vines (up in the air, of course) so that you see the walk in blazing sun, then dark under the vines, then (at the far end) in brillant sun can have good effects from roses of the most day-glow brilliance. They are set off by the dark bower in front of them.

There such a rose as 'Tropicana' may show itself off.It can be handsome with purple-leaf plants around it, or with plenty of gray leaves. But it seems to me a mistake (the rose itself is a mistake, as far as I am concerned, because I have no aptitude for these neon colors in roses, but there they are) to use such a color in beds of rose and pink and crimson and yellow roses, for there the strident color wars with and dominates everything within sight. But when given rather a place of honor, in blazing sun and contrasted with deep shade, such a rose as 'Tropicana' can be glorious.

If you like it at all.

Dark crimsons, by the way, and intensely rich violets and mahogany and bronze -- what sumptuous colors they are. And yet in a garden they invariably give a heavy dull effect when used by themselves, and what is strangest of all they become invisible at 30 feet. You discover, after a bit, that rich as those colors are, they do not give rich effects, excect when used with other colors. Straw yellow -- a color that hardly anybody starts off admiring -- is one of the most useful of all colors, as you will quickly see if you try it with these rich bronzes and crimsons.It makes them come alive, and so does fairly pale magenta.

Yellow irises (to give an example here) are great favorites of mine, and once I though they would look fine contrasted only with sky-blue and white irises. Theoretically they should have looked good, since the colors were all pure and sparkling. To my surprise, the effect (which I had feared might be to brassy, contrasting the yellow and blue) was distinctly tame and yawnworthy.

"I warned you to use plenty of wisteria lavender and sweet-pea pink," said an experienced gardener at the time, surveying my dull effect and quite pleased (for gardeners are not angels, let me tell you) to see it had worked out as badly as she had predicted.

As it happened, that mauve-magenta sweet-pea pink is a color I cordially dislike. But the next year I included the lavenders and off-pinks, as instructed by my friend, and over my dead body of course. Needless to say, the same yellows and blues came brilliantly alive. Thanks to the washy lavenders and maddery rose pinks.

One of the most glorious of all colors is royal purple, and fortunately you find it in irises as in no other flower. I have noticed that men tend to go hogwild with it, as I have so often done, and then wonder (as I did) why the effect was not as opulent as they thought it would be. One of the great disappointments of my life was the discovery that rich purple loses its effect unless used very sparingly. A few blobs of rich purple is fine -- but if planted as freely as I would like, it becomes lifeless, however gorgeous the color may seem in an individual flower.

Thus experience forces us to learn a little, and after years of muddling about we usually discover (often late in life) what "everybody" has always known:

Soft and non-brilliant yellows and soft unspectacular lavenders and grayed blues and clear but not aggressive pinks are endlessly satisfying. Then you add extremely little deep purple, virtually no mahogany red, virtually no bronze (though it is beyond any gardener's strength to omit them entirely) and the result suddenly becomes marvelous.

White is commonly recommended -- by the blind, I have often suspected -- as a great pacificer of warring colors. I find it eggs on the warriors rather than reconciles them. White can behave like a spotlight, throwing everything else out of key. Of course there are many whites, some of the yellow side, some on the blue side, and the yellowish whites are the easiest to live with.

No harm at all is done if the colors don't seem quite right to you at first.

Simply move the plants around until you like them better. When you shift things about you get a good many surprises, and commonly one partner of an especially satisfying color group will promptly die, or else grow out of bounds. That sort of thing we all know very well. No matter. We just keep at it, and presumably we will get it all worked out the year after we die. k

But along the way we really do learn that marigolds gain enormously in impact when used as sparingly as ultimatums. We learn the pitfalls of too much brilliance, in which the gorgeous ones cancel each other out. In colors, as in humans, we learn there is much to be said for the modest, the pure and (God save us all) the relatively dull.