Two very good books, one about flower arranging and the other about growing plants indoors, have just been published.

The first is "Design With Plant Material," By Marian Aaronson (Grower Books, London, England, distributed in the U.S. by ISBS, Inc., 2130 Pacific Ave., Forest Grove, Ore., 118 pp., well illustrated $11.95).

Aaronson is an internationally known flower arranger who has traveled extensively to teach, lecture, judge and demonstrate the art of flower arranging. Over the years she has developed an individual style that is progressive and inspiring to others.

"The character of flower arranging has changed considerably over the years," she says. "New concepts, new theories, new images, have carried it to a wider, larger sphere, where flowers and their arranging are only a part. As in the other arts, a greater range of materials and ways of usage becomes valid for designing purposes.

"Furthermore, greater knowledge, experience and understanding has developed a strong appreciation of design, which has raised flower arranging to a highly artistic level, from a mere decoration to a creative art form.

"In the early stages of flower arrangeing the design principles are studied, the simple basic styles practiced. Once mastered, the arranger should reach out for something more challenging and move to a more advanced level. The eye is now more trained to what is balanced, pproportionate and harmonious in a design. Knowledge and experience should give the confidence to adapt the general to a more personal pattern, to be imaginative rather than repetitive.

"One is guided by the same principles and the aim is still for an orderly, rhythmic pattern, but the designing procedure can be varied and the principles modified considerably to suit a particular style or situation. This gives greater flexibility and freedom to be creative.

"With balance, for instance, one is taught at the beginning that the lightest item (in visual weight), the palest color, the smallest form should be at the top of the design, the heaviest, darkest and the largest form at the base.

"As one progresses it is possible to alter this for different styles, often to produce a more interesting balance. Sometimes perfect balance produces a static effect and experimenting with a line, form, or color out of balance can bring about a more lively and stimulating composition."

With 12 full-color plates and over 60 black and-white photographs, Aaronson illustrates her conclusion.

The second book is "All About House Plants," by Montague Free, revised and expanded by Marjorie J. Diet (Doubleday, 365 pp., well-illustrated, $12.95).

The late Montague Free was a horticulturist at the Brooklyn Botanic Garden for 31 years and served as a senior editor of Flower Grower magazine. Dietz is a former editor of Plants and Gardens, Brooklyn Botanic Garden publications. With more than 180 new color and black-and-white photographs, the book provides comprehensive instructions on how to care for over 1,000 popular plants in the home.

Some of the plants recommended in the first "All About House Plants," although rarely grown today, have been kept in the book, Dietz says, partly for the record and partly because their time may come again.

"A practice nearly rejected for this revision," she says, "was the sowing of sweet-alyssum seeds in eggshells for Easter favors. My first reaction was, now who would want to do that? But this was quickly aced replaced by, what an intriguing idea! And I for one intend to try it.

"When I once worked for a New York florist and tended house plants in the houses of the affluent," she says, "I noticed that in neglected window boxes Dracaena sanderana was the plant that survived after all the others had gone to their last rest.

"The Snake plant, Sanseviera trifasciata 'Laurantii,' is one of the most inelegant of all plants, with its stiff 30-inch, upright leaves and the entire lack of form of the plant as a whole. Its yellow stripes, however, do provide a color note; but its chief claim to consideration is its toughness and ability to survive in darkish corners under conditions of neglect. It is erratic in its blooming habit, occasionally sending up its spike of fragant flowers at unpredictable times. They are yellowish and not particularly ornamental, but their fragrance is welcome."