To dwell in the city and yet be able to withdraw from it at the same time sounds like an impossibility, yet it can be achieved through a city garden, a green oasis tucked away behind an austere facade, according to Alice Recknagle Ireys, in her new book, "Small Gardens for City and Country: A guide to designing & planting your green spaces," published by Prentice-Hall (210 pages, beautifully illustrated, $14.95 hard cover, $8.95 paperback).

Ireys is a practicing landscape architect in New York State, lectures to garden clubs and design schools and has been an instructor in landscape gardening at Connecticut College for Women.

The purpose of this book is to give ideas and suggestions for small gardens in city and country. Some people may prefer a formal layout with a pattern, clipped hedges, and clean-cut lines, other may love free-flowing curves with unrestricted planting. This book will lead you through the gates of many small gardens tucked away behind old houses in the city as well as into out-of-town gardens scattered throughout the country.

Perhaps the most important reason for being an organic gardener is that you avoid starting chain reactions in the environment from poisonous chemical sprays and dusts you might introduce or other chemicals whose effects can spread all over your garden or your entire area, according to Catharine Osgood Foster, in her new paperback, "Organic Flower Gardening," published by Rodale Press (305 pages, well illustrated, $7.95).

The best garden housekeeping will involve methods that enhance and support the life networks of interrelationships, she says. And natural methods are the most appropriate, most coorperative the best.

Cactus and some other succulents are examples of nature's ingenuity in adapting plants to survive in environmental extremes. The deserts of the world contain most of them and they are found also in jungles and on mountain tops.

They are becoming widely used as house plants - lovely to look at, and easy to grow. Whether you enjoy them for their flowers, foliage or form, they are probably the most fascinating group in the entire plant kingdom.

Another interesting wrinkle is: growing cacti from seed (they are listed in seed catalogues) and creating oddities of plant forms not found in nature by grafting a part of one onto another.

It isn't difficult and the know-how is provided in a new paperback, "Cactus and Succulents," by the editors of Sunset Books and Magazine, published by Lane Pub. Co., Menlo Park, Clif, (80 pages, many illustrations, some in full color, $2.95).