Q A friend of mine has an immense hoya plant which she is very fond of, but it has white insects covering the leaves. None of the pesticides she has tried so far has done any good. I told her I would write for your all-purpose spray, which you mentioned some time ago in this column.
It sounds as though your friend has mealy bugs on her hoya (wax plant). Commercial pesticides get only the juvenile, crawler stage of this insect. The adults have a waxy, cottony covering that makes them invulnerable.
Here is the homemade spray that will penetrate the waxy shield: To 1 gallon of water, add 1 tablespoon each of liquid dishwashing detergent and hot Tabasco sauce, plus 1 quart of rubbing alcohol. Each leaf and stem should be washed with the solution.
She may have to cut off the runners, seal them in a plastic bag, and dispose of them to get the parent plant to manageable size. Then she can eradicate the infestation.
Thorough drenching and flushing 3 times at 7-day intervals may eliminate them , but crawlers are in other places in the room. Hoya carnosa is referred to as wax plant because of the waxy, fragrant blooms.
Q I have a potted purple-leaved (hairy) plant which I call purple velvet plant. I do not know the real name. It has orange daisylike blooms that have an unsavory smell. At first it was shiny bright purple, but now it is getting vinelike and the leaves are turning greenish. How can I bring back the purple?
The plant probably lacks sunlight. At least four hours a day will help keep the purple in the leaves of Gynura sarmentosa (also called purple passion plant).
It needs regular pinching of the tips to keep it compact and to keep the new leaves coming. The new leaves will have more purple than the older leaves.
Q Could you mention a hanging basket plant that is easy to grow and that will do well in subdued light? I have tried heart-leaved philodendron, and it gets straggly within a few months. The spot gets light from across the room, but no sunlight, since it's the northeast corner of the house.
Try growing devil's ivy (Scindapsus), often referred to as pothos. The leaves' shape resembles philodendron, but the foliage is green and white, or green and cream, depending on the variety. The green will predominate if the light is very poor.
Scindapsus does not do well if the temperature falls below 65 degrees F., but will grow in artificial light entirely if it has about 400 foot-candles.
The vines also will thrive in a vase of water.
Q We planted a purple lilac bush three years ago, and it was doing well until last spring. When the leaves came out, they were small, and later the blossoms turned out to be tiny white ones. The bush resembles the ones in our neighbors' privet hedge. Have you ever heard of anything so strange?
Most lilacs are budded (a form of grafting) onto a root stock of privet. Adverse situations, such as severe winters, dry weather, or borers, can destroy the lilac portion, whereupon the privet from below the bud union merely takes over, growing into a full-size shrub.
Q When I try to repot a plant, even a little one, I have a terrible time. I can't seem to get the plant out of the pot without mutilating the roots or breaking the pot, even though I lay it on its side and run a spatula around the edges.
With pots up to 8 inches in diameter, the best way to loosen the root ball from the sides of the pot is to use a solid shelf or table. With both hands, spread your fingers over the top of the soil, keeping your thumbs on the rim of the pot. Then invert the plant (pot and all) and give the rim of the pot a sharp bump on the shelf. The soil ball should fall out into your hands.
Larger plants can be laid on the side, where the pot can be struck on the rim with a piece of wood. Strike it in several places (as if you were bringing the shelf to the pot), and gently pull on the plant. You may need a long spatula to get the root ball started.
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, authors of several books on gardening, and greenhouse operators for more than 25 years.m