LET US now think what is wrong with flowering cherries and go right on from there.

It often comes as a thunder clap to the innocent (not that gardeners remain innocent long) to be told that flowering cherries have major faults. So do most ornamental plants.

First, the cherries have fierce root systems and fill the earth with them. Second, their shade is dense. Between the roots and the leafy canopy, it is hard to grow anything at all near a flowering cherry.

Besides, their foilage is uninteresting. The cherry is not worth looking at when its one-week flowering season is past.

Many otherwise sensible gardeners, however, so admire these trees that they put up with these faults.

The proper place for flowering cherries is on Mr. Fuji, or around the Tidal Basin or in the suburb of Kenwood, where they can be glorious in their season and where I do not have to look at them for 50 weeks a year.

The flowering crabs are somewhat better. Not much. They are as lovely as the cherries when they bloom, and they have a second season of interest, when the fruit colors in the fall.

There are now many crabs that do not see fruit, but I would not have one of them. It is like a dog that can't wag his tail.

Among flowering crabs, the two best ones are Malus hupehensis and M. sargentii.

And yet I admit that virtually any crab apple tree is irresistible in bloom, and many of the new ones are said to be disease resistant and I know many people do not care whether the tree is covered with little apples in the fall or not.

Still, health is not everthing. Beauty has claims.

Now the native beech and the European beech agree in making it impossible to grow anything beneath them except maybe pachysandra. They are greedy trees. Bad, bad, I always say when I see the beech.

No tree is more beautiful, unfortunately, and none is nobler in effect. They live forever (as far as mortal gardeners are concerned) and are beautiful in foilage or bark and outline at all seasons. They are an extremely poor choice for small gardens. And yet I can understand the innocent gardener's being seduced by the beech tree far more easily than I can understand the lush temptation of flowering cherries.

The Norway maple is a tree to be avoided. Not surprisingly, the loons who lay out cities are fond of it -- sufficient warning, I would think, of its defects.

Its roots are worse than anything except poplars and willows, but unlike those two equally greedy trees, the Norway maple makes a dismal gloomy shade. It turns glorious yellow in the fall -- to give the devil his due. It is one of those trees that makes New England look wrong.

New England is full of rocks and ice and weathered wood and plenty of Norway maples. God was just, sending the Puritans there.

Hemlocks are equally wretched trees. Nothing is gloomier than the shade of hemlock. The position that killed Socrates was not this tree or any other, but an herbaceous plant. Still, I am not surprised that people suppose it was the hemlock tree that killed that sweetest of philosophers. It certainly looks the part.

The hemlock belongs in the great forests of North Carolina, where indeed it flourishes through the cold rainy late summers of those mountains. Drip, drip, drip, and it grows like mad.

If you should have a garden located in the shade of a neighbor's hemlocks, you might as well forget gardening and settle for plenty of stone, plenty of ivy, and a pool of water, spending most of your budget on a first-rate sculpture.

The red maple of our woods is pretty rooty, too, but it is a far more civilized tree than the Norway maple and you can grow other things near it. Also, it redeems itself by its velvet haze of red flowers on naked branches late in winter, and its yellow and red leaves in the fall.

Still, when you consider the number of maples ideal for small gardens, you wonder why people so consistently choose maples that will complicate their gardening life for the next half-century (or however long the gardener has left).

The japanese maples are splendid in small gardens. I do not think substantial efforts should be made to keep them from looking Japanese. Anything remotely resembling a stone lantern should be moved back near the dog's house where it will not readily be seen.

I am sorry, but not surprised, to see that red-leaf varieties of the Japanese maple are popular. The green-leaf sorts are handsomer; since the new gardener will come to that conclusion after a few years, he will do well to avoid the red-leaf sorts in the beginning.

The cutleaf forms of these maples look extremely self-conscious, and I have always desired one more than anything.Again, the green kinds wear best. And yet, if it is made the focus of the garden, the red cutleaf maple is so beautiful that all arguments collapse before it. There is one on Northhampton Street I regularly drool over.

Of the green maples from Japan, some turn deep crimson in the fall, others blood color (there is more scarlet in blood than one remembers until he sees it anew) while others turn yellow and orange and chartreuse with rose flushes and so forth. 'Osakadzuki' is especially gorgeous in flame red, but you want to give all these Japanese maples a setting like a forest glen. They do not think well of windy sunbaked sites, and they do not care for clay that bakes to brick. Give them the sort of place you would give azaleas.

A small maple we shall increasingly see -- and shall be increasingly happy to see -- is Acer griseum, with bark that shreds and curls. It behaves with the good manners of a hawthorn, and its fall foliage leaves nothing to be desired in rich color.

The evergreen magnolia, the bull bay, the great magnolia of the South, is unrivaled in the glossy magnificence of its leaves. It is not showy, even in full bloom, but the individual blooms are spectacular. I grew up embowered by these magnolias, and have put them away with other childish enthusiasms like Tootsie Rolls.

No tree, I gladly admit, is more beautiful than this magnolia, and hardly any other tree approaches it in its majestic brand of loveliness, but I do not have a place for it to show itself off.

It is a forest tree, but it is handsomest out in the open with its branches sweeping (or defiantly thrusting) to the ground. Inside, of course, is a rat's nest of old leaves, the droppings of immemorial generations of starlings, etc., but these need not be thought of or seen, if the tree is left alone.

Or, if the lower branches are sawed off, (a thing frowned on in the South), the tree can be kept very neat and even some sunlight can be admitted to the downstairs windows of the house.

In England they have-or had, for they are gradually learning -- a passion for training this great tree flat against a wall. Even apart from the fact that it takes one man full time to pick up the leaves the magnolia democratically drops every day of the year, New Year's included, a great deal of work and anxiety is involved in keeping the tree against the wall.

Like the Southern matron, the magnolia keeps bosoming forth and has no desire at all to remain demure against the wall. In any case, no wall smaller than the Capitol will accommodate it.

Once in our town a magnolia tree died. People came from all over to see it. We had never seen, or heard of, a dead magnolia tree. I know that any magnolia will succomb if its roots are tampered with. In my country, however, nobody ever had the spare madness or ambition to go digging around the roots of magnolias.

Far more suitable for small gardens is the star magnolia, Magnolia stellata, which blooms in the first mildness of spring and is often frozen therefore. No matter. No tree in all the world is more graciously opulent (rare combination) in flower, and its scent is superior to that of the great bull bay, having an undertone of both clove and lemon.

Other Asian magnolias are also splendid for suburban gardens, or even town gardens large enough to have a tree the size of an apple. The pink "tulip tree" or M. soulangeana is common and superb. Smaller and even more suitable is M. liliflora nigra, dark red purple.

It is smaller, narrower, not so tall, and blooms a few days later, and puts out occasional flowers through the summer, not enough to make any show, but sufficient to make a nice little surprise for the observant gardener. s

Among the least suitable trees for small gardens I should mention the weeping willow and Lombardy poplar. They happen to be among my favorities of all trees. The roots of both are, in a word, outrageous, and I believe they can get into a foundation and bring down the house. Well, get a new house. Of course, reason finally prevails, but I have had no more persistent temptations in my life than the desire to grow these two trees. Never have. If I lived in the country or had a big sunny lot and didn't want to grow a lot of stuff, I'd plant them both.

The fact that they are quick-growing, fragile in storms, subject to various deseases and so forth, does not diminish the true fact that they are supremely beautiful. How I wish people two doors away would grow them.