Q I recently read, and then misplaced, an article about an edible tuber called Camassia. Today I received a spring bulb catalog and it lists Camassia esculenta, also called Camas. It is described as having a flower stem 2 to 4 feet high with hundreds of star-shaped rich purple flowers. Is this the same bulb that is an edible tuber? D. F. Dover, Del. Yes, Camassia esculenta, also called quamash and camass (sometimes with one ``s''), was once the major food source of the Indians of the Northwest.
Avant Gardener, a horticultural news service, tells us Dr. Roscoe Watson, former professor of plant pathology at the University of Idaho, has (with retired professors) formed the nonprofit Mariposa Foundation for Conservation (of this bulb), University Station, Box 3037, Moscow, Idaho 83843.
It is reported that horticulturist Luther Burbank said its flavor and texture were so good it could compete with any tuber bearer, including the potato. Many bulb and perennial catalogs now list Camassia, and in some it is available in white as well as blue. Q I am curious about our lawn. Each time my husband mows, the grass takes on a grayish cast. Our neighbors have the same type of grass, but it always looks nice and green after they finish mowing. H. E. G. Bowling Green, Ohio
When lawns take on a grayish or yellowish hue right after mowing, it is because of a dull mower.
If it takes on an overall brownish appearance (not caused by dry weather) and neighbors' lawns remain green after mowing, then the mower blades are set too low and you are scalping the lawn. Keep blades sharp and set at 11/2 to 2 inches for normal mowing. Q Quite some time ago you had some wonderful facts about the value of trees. I am a teacher and want to do a project about trees and other green plants. Would you mind giving those facts again? J. S. Torrance, Calif.
We start sessions with children (near trees, if possible) by asking if they would like to live on the moon where temperatures go from minus 243 degrees F. to plus 213 degrees F. during a lunar ``day,'' and where there is no rain. We ask, ``Is there oxygen on the moon? Are there any trees?''
Our discussion evolves naturally to the fact that trees do many important things: they moderate climate; take on carbon dioxide (and other wastes) and convert it to oxygen for breathing; give off moisture that eventually becomes rain; give humans, and other animals, food and homes; make it warmer in winter (windbreaks) and cooler in summer (it's 25 to 30 degrees cooler under trees); give us paper products; and on and on.
An excellent section on trees can be found in the ``Audubon Nature Encyclopedia,'' put out by the National Audubon Society. Q At your suggestion I started some Sweetheart strawberry seeds. The plants grew well after transplanting into a large hanging basket. The berries were delicious and delightfully ornamental for about 4 months. Then the leaves became yellowish and rather mottled-looking. Soon I noticed some webbing on leaves and sprayed with a commercial houseplant spray but it did no good, even though I fertilized, also. I finally dumped the whole mess out of the planter into a plastic bag destined for the dump. What could
have gone wrong? S. B. Charlottesville, Va.
You had spider mites, which are not insects (having 3 pairs of legs) but are arachnids, having 4 pairs of legs, plus other differences.
Most all-purpose commercial sprays will not affect them. Misting foliage (all over) every few days will help, because moisture makes the mites bloat.
More effective is our homemade formula: To one gallon of tepid water add 1 tablespoon each of liquid dishwashing detergent and hot pepper sauce, plus 1 to 2 cups of rubbing alcohol.
The secret is to drench foliage every 6 to 7 days until infestation is gone, then give the plant a liquid feeding.
To detect mites in early stages, hold white piece of paper under foliage and tap leaves sharply with pencil. If you see tiny, crawling, dark specks, those are mites and you should spray immediately.
If you have a question about your garden, inside or out, send it to the Garden Page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. Doc and Katy Abraham are nationally known horticulturists.