Q We love spider plants; however, each time we get one it develops brownish scales. Although the scales are mostly on the stem runners, eventually they get on the leaves as well, and the plant gets very sticky. What can we do to get rid of the scales and prevent them from coming back?
The scale insect has a coat of armor protecting the tiny creature underneath. They exude a sticky ''honeydew'' as they suck juices from the plant.
The plant can be put inside a plastic bag in which is enclosed one of the yellow waxlike pest strips. Set it in a cool spot (60 to 65 degrees F.) and out of the sun for about a week.
If you prefer, you can use an all-purpose formula: One tablespoon each of liquid dishwashing detergent, liquid hot sauce, and one quart of rubbing alcohol in a gallon of water. Using a soft cloth, sponge off all parts of the plant with the solution. Repeat in about 10 days.
Repot in a clean container and see that any fiber plant hangers are washed thoroughly. Insects are carried over in the hangers as well as in any cracks around the windowsills.
Q Last spring a friend in Oklahoma showed me a purple-green, mound-shaped plant with tiny yellow flowers. Yellow leaves surround each cluster like a collar. It has milky juice and she calls it ''yellow cushion plant.'' My friend says she would like to send me a division, but I'm not sure it would stand the Wisconsin climate. Do you know its real name?
This striking plant is Euphorbia polychroma (also E. epithymoides). All Euphorbias, including poinsettias, have milky juice. Yellow bracts surrounding the blooms are similar to the red bracts on poinsettias, except they are much smaller. The purplish leaves change to all green during the summer and a striking red in the fall.
You may find it listed as cushion spurge. Neat growth habits and adaptability to cool climates, such as Wisconsin, as well as to the warmer climates of the southernmost states, make it a much-desired perennial.
Q Last spring we planted three peach trees. The grass now has grown around them, and I would like to know if I should remove the sod and cultivate around the trunk or just let the sod remain?
Peach trees are shallow-rooted, and research has shown that cultivation damages the roots and contributes to peach-tree decline.
It's a good idea, however, to remove the grass and sod in a circle around the trunk about 12 inches in diameter and replace it with shredded bark if you're going to mow around the tree. This prevents mower damage.
Removing tall growth around the trunk and painting the trunk with latex paint help prevent borer damage.
Q Some time ago you wrote about a tree that has lacy white blooms in the spring and purplish fruit in June. It had several names, and the only one I can remember is Shadblow. I have looked through several catalogs and cannot find it under this name. Would you please repeat some of the names so I can locate it.
The tree you refer to is Amelanchier (a-muh-lahn'-key-uh), also called Juneberry and Serviceberry.
The American Indians were said to have used the berries in their bread. The berries are tasty, fresh or cooked, for jams and desserts. The trees are extremely hardy, but also tolerate warm climates as far south as parts of Texas and Louisiana.
If you have a question about your garden, send it to the Garden Page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115.