The principles of the Persian garden are ideally suited for town gardens in regions utterly different in climate from the desert land in which they originated.

Not many gardeners want a garden that shouts "Persia" at them, but a garden may be essentially Persian in design without oriental touches in the way of Islamic tiles, water basins shaped like lotuses, and so on. The details can be quite Western.

The essential nature of Persian gardens is enclosure -- the world shut out -- and a dominant emphasis on water and enough foliage to suggest an oasis. The cost of high walls is prohibitive, but such ordinary (and marvelous) plants as native red cedar and holly will easily make walls of green sufficient to serve the purpose. The practical point of Persian water tanks and channels is irrigation, and that is not necessary in most American gardens. Still, our gardens are hot as the hinges for that part of the year when they should be used the most, and nothing is better than a fish pool and a shaded bower to view it from.

A kind of summerhouse, which can be as simple as wooden posts and a roof of wooden trellis, could be built by the house entrance to the garden. It could be paved with brick set right on the dirt, and in small gardens, perhaps only 25 by 40 feet, the paving could continue, instead of grass, to a raised pool for waterlilies and fish.

The pool does not need elaborate pipes and drains. It does not need anything at all, and can be drained and cleaned once a year or once every two years. It can be as small as necessary, but 10 by 12 feet is not too large for the space being considered here.

On the summerhouse or arbor nothing is better than a grapevine. Nothing makes better shade, but such vines as actinidia, akebia, clematis, wisteria, trumpet vine and honeysuckle are all obvious choices. If you preferred, you could have a rosy honeysuckle at one side and keep the other side free for annual vines. The moonflower (Calonyction aculeatum) would be agreeable if you sat in the garden much on summer nights, or morning glories might do for those gardeners who arise at 5 a.m. Cardinal climber, nasturtium, eccremocarpus, cucumber, gourd or virtually any other climber that dies in the winter could be planted on one side of the sitting pavilion to go with the clematis or honeysuckle on the other side.

Flowers in such a garden should be of great beauty, as there cannot be many of them in a 25-by-40-foot garden. Roses, lilies, daffodils, irises, tulips and crinums all come to mind, in narrow borders beneath the green walls, and at the edge, right against the pavement, any number of modest little things could be worked in -- Brodieaea uniflora, arabis, alyssum, sedum, epimedium, dwarf annuals such as nasturtium.

By keeping the trees (not really trees at all, but eight-foot junipers and hollies or yews used as a hedge) at the boundaries of the garden, and by keeping the center paved solid with brick or other substitute, with the big pool for waterlilies and fish, the garden would not seem absurdly crowded. If you thought the brick paving looked overly generous, you could set a few tubs about with, say, speciosum lilies or angel trumpets or figs or bananas in them.

Plenty of luxuriant growth, a glittering patch of water with red fish swimming about and a place to sit and admire it all are the gist of such a garden.

The Persians never counted on flowers in the summer. Their flowers came after the snows melted and lasted through the roses -- altogether about 100 days. Through the hot summer they counted only on cool shade and water, and maybe some colorful tiles. We, of course, have wonderful waterlilies that they did not, and Japanese anemones for the fall, and maybe some autumn crocuses and sternbergias. Chrysanthemums, too, if you wanted to give space to them.

There is nothing wrong with concrete, by the way. It need not look like a sidewalk. Earth colors (yellow oxide of iron makes a soft buff color) can be added to the dry mix, or the mix can include sphagnum peat so that it weathers to look like sandstone. So don't feel bad if cut stone or even brick seems to be too costly.

Most people would never know the garden was Persian in origin. A thing the Persians did that I very much like was to plant fruit trees among the cypresses. Peaches, pears and plums all look fine with our red cedars and hollies, and the evergreens give weight to the otherwise too soft and too ordinary look of the fruit tree foliage.

John Brookes has a new book. "The Paradise Garden," with many illustrations and plans, makes an excellent introduction to the subject, and there are other good books, among them "The Gardens of Mughul India," by Sylvia Crowe et al.; "The Islamic Garden," an excellent summary of a Dumbarton Oaks seminar, edited by Elisabeth Macdougall; "Paradise as a Garden," by Elizabeth Moynihan; and "Earthly Paradise," by Jonas Lehrman.

Often, even if the gardener does not want his small plot to look as if it had just dropped down from Esfaha'n, reading a few books on Persian gardens (the prototype of Islamic and Mughul gardens in general) will help the modern American urban gardener to see what is important in a garden and what is not. Many city gardens could be simplified, enriched and made vastly more beautiful with a little attention to the principles and examples discovered so long ago by the Persians.