THE FATTEST and most scrumptious of all flowers, a rare fusion of fluff and majesty, the peony is now coming into bloom to mark the highest of high spring.

Most of my scruples against ponderous shapes in flowers are swept away in the general confusion of the peony season. I say confusion only because I have never been able to settle down with a handful of varieties I consider the best.

It is gradually becoming clear to me that if I had space from 200, there would still be a few hundred more to be desired and, worst of all, I have never had the chance to grow a few hundred so that at the last (that is, in a small city garden) I could settle for a handful to serve as well as a thousand.

When I was a boy there was an old man who sold peonies and opened his garden once a year for the town to admire. There you placed orders and in due time, late in September or October, he showed up to deliver the root.

His favorite was "Le Cygne" a swan of a flower indeed, though not as hearty a grower as one might wish. As far as I know he had no other plants but peonies, and when they were over, he aestivated.

When he was in his 90s, he dropped by unexpectedly - since I had no ordered anything in the spring - and said he wanted me to have three roots, "Festiva Maxima," "Monsieur Jules Elie" and, I think (for I did not grow it) "Edulis Superba." He died a few days after that, and I suspect he thought the time had come to go around and make sure plenty of people were growing peonies, and that he had better start them off right with a few that would grow and bloom well for anybody.

I never see those varieties but I think of him. "Festiva Maxima" is the fat double early white and occasional crimson flecks that you see everywhere. It was bred and put on the market in 1851.

The second, which is one of those rare flowers of which gardeners manage to get the entire name right, "M. Jules Elie," is a huge medium pink, the petals curving up somewhat like a chrysanthemum, and the color somewhat veiled by silver-gray. But do not imagine it is a dull color - it is flawless and as luscious as strawberries in cream.

The third, which came out in the 1820s, as I remember it, is a sort of rose pink, a trifle too blue to suit many gardeners, and round and not too large. But like the other two it blooms early in the peony season and is, of the three, the most perfumed.

It used to be a great cut-flower variety, and once or twice I have seen it at flower stalls in Washington.

To bring some sort of order to the peony tribe, for gardeners who may not be familiar with them, let me mention the general types:

First, there are the full doubles, very like dahlias that have gone to heaven and been transformed. These are the tremendous sorts that girls used to carry in bouquets for graduation day from high school in the North. Many of them are big as a cantaloupe. When the petals fill with rain, most of them bend down on their stems and never quite stand up straight again. Needless to say, it is prudent to provide wire rings or stakes for them.

Second, there are the semi-doubles, with fewer petals. The anemone-flowered kinds have a row or two of flat outer petals - not always flat, come to think of it - and thinner petalodes, like shredded petals, in the middle. Sometimes they have yellow stamens showing, sometimes not.

The Japanese peonies are somewhat similar, only with the stamens transformed into floral parts. That is, there is a great flat saucer of petals and a grand sunburst of stamens looking like yellow confetti in the middle. Sometimes the Japanese sorts have the middle the same color as the petals, which is very handsome, and sometimes there is a contrast. These great single flowers, once quite expensive, are now as cheap as any other sort of peony.

Some are red with yellow centers; some white with tawny gold; some pink with red centers; some rose with whitish centers; some vaguely lavender, and in some the pink petals are edged with lighter color.

Having only the single row of petals, they do not get waterlogged so badly as the massive doubles, and they stand up better in rain.

It is not true, however, that you need not stake them. Last year my "Largo," a deep rose with yellow centers, flopped about in the rain and covered a circle five feet in diameter. It is merely one of many spectacular varieties, and I also grow "Christine," a white; "Westerner," a rich wonderful pink; "Plainsman," blush; "Sitka," another white, and "Chocolata Soldier," a glossy red with occasional yellow dots on the petals, one of the earliest kinds.

"Gay Paree" is pink with red centers; "Doreen" has several tints of pink in it; "Sword Dance" is a late-flowering red and yellow; "Isani Gidui" and "Toro-nomaki" are whites with yellow centers. And there are dozens of others, all of which I would grow if I could.

This may be the place to say that lists of the "best" varieties are inherently absurd, since if you dislike deep red with yellow centers, you clearly should not grow reds with yellow centers, no matter what list they appear on. Likewise, if you think the whites with yellow are too elegant, and want something flashier, like pink and yellow, then clearly you should grow the pinks.

Most lists provide a wide assortment of types and colors, and I dearly love lists of the best this and the best that, but I never follow them very closely in my own selection. I do not think a gardener can go wrong with peonies, except in two ways:

He can wind up with so many of the massive doubles that the effect is heavier, when they are in flower, than he intended. Second, he may not be prepared for the staking that the heavy kinds require. Apart from that, I don't see how anyone can go wrong.

Some of the very double kinds, especially the late-season ones, will fail to open properly in hot weather. They are a gamble, and to begin with, the gardener should perhaps concentrate on earlier-season sorts.

I have not mentioned the singles. These have a row of petals, like the Japanese, but lack the big central tuft. Such varieties as "Dawn Pink" "Sea Shell," "Krinkled White," "Pico" and "Le Jour" are among the esteemed sorts.

Also I have not mentioned the hybrids - peonies in which more than one wild species is in the ancestry. As a group, these bloom earliest of all, and their colors are especially brilliant. Or fierce, if you prefer. They bring the fire of the Oriental poppy to the garden before those poppies bloom, and since they are strong in orange-reds, intense cherry, etc., some restraint (if possible) probably should be exercised.

Well known kinds, besides "Chocolate Solider," which has the Japanese form of a central boss, include such single reds as "Bright Knight," "John Harvard," and such full doubles as "Red Charm," which virtually everybody likes since it is fully and clearly red without setting off the smoke alarms, and such whites as "Requiem," a flat lightly built bloom. There are also many curious pinks, and many creamy cerises - colors othwise lacking in garden peonies.

Among the doubles, since they are entirely too gorgeous to gloss over, are "Florence Ellis," "Mrs. Franklin D. Roosevelt," "Nick Shaylor," "Myrtle Gentry," all considered pretty reliable pinks. Whites include "Kelway's Glorious," "Mary E. Nicholls," "Elsa Sass," among many; and good reds "Kansas," "Philippe Riviore," "Karl Rosenfield," and "Richard Carvel." Again, let me insist that one should not assume varieties not listed are somehow maybe not as good as those that are.

"Big Ben," for example, is not found on lists of the "best" reds, I think, but it is tall, early, reliable, and one of the very best for the South since it does not fail to open properly.

Peonies should be planted in October, the growth points or eyes (those fleshy red swellings on the roots from which stems emerge in the spring) just barely covered. No more than an inch of dirt over them. They should be given full sun, if convenient, or at least as sunny a place as one has. They will not grow under trees, like azaleas, and they like good soil such as tomatoes require.

The sensible thing (although I am quite aware I am dealing with gardeners) is to decide how much space can be given to peonies and just where.

All gardeners like to say, "Well, now, let's just go through a few catalogs," and they make tremendous lists and fidget over them for a while, then (as July arrives) cut them drastically, and finally (as October approaches) madly order a few peonies almost at random, having forgotten which ones they were so keen about in May.

There is a public display garden of peonies in the National Arboretum, well worth a few visits, and they are labeled, of course.

Once the gardener decides he can manage half a dozen, or three, or 26, or whatever it is, he should have a precise idea which spots in the garden they will occupy, and this will prevent color clashes, assuming the gardener can remember that the fiery climbing rose "Dortmund," does not look so hot with the pink Japanese "Sky Pilot." Likewise, certain tender-colored pink peonies do not blend (except in a whirling sort of way) with certain fiery orange poppies that may bloom at the same time.

If planting stations are prepared now, digging in plenty of humus and some manure (but no manure at planting time or around the stems in future years, since it is supposed to invite fungi and rank growth both) then a stake can mark the spot, and the whole thing may be allowed to settle without attention until October. Then pull up any little weeds that may have been missed, and plant the peonies about Oct. 10.

Most peonies have excellent foliage. Even when out of bloom, the plants have a solid air, as if the gardener knew what he were doing, and this of course has endeared them to gardeners for centuries.

Many of the hybrids, however, die down in late summer or even as early as late July, and this is alarming the first time it happens. One cannot imagine the plants will be healthy and vigorous the next spring, but they are. Do not plant the hybrids (such as "Red Charm"), therefore, in a place where you require fine foliage in the fall.

A book, "Peonies Outdoors and In," by Arne and Irene Nehrling (Dover Publications, New York) is an excellent thing and can be found at public libraries.

High quality dormant roots, with three to five eyes, will cost about $2.50 each this fall, for standard sorts bought in collections - say, four different Japanese peonies for $10 - and a bit more for kinds in short supply.

Try not to go hog wild. A peony will occupy a circle 30 to 40 inches in diameter, as a rule, and nothing else will grow in that space. Also peonies abhor tree roots and grass. They greatly dislike being moved, once they settle in. Like irises, they like the best spots in the garden. So do roses. Try to be careful, remembering peonies only bloom a few weeks - an individual plant only a few days. But don't be too restrained.