Q: Do I have to prune my crepe myrtles every year? What happens if I don't?

Johnny Allan, Sandy Springs

A: You don't have to prune every year and the plants won't die if you leave them alone. Pruning is done for aesthetic reasons. Dr. Gary Knox at the University of Florida did a crape myrtle pruning experiment comparing no pruning to pencil pruning and to topping. His conclusions:

• Unpruned trees require the least overall work.

• Pencil-pruning takes more time than topping.

• Topping stimulates more sprouts.

• The harder you prune, the more you delay flowering.

• On 'Natchez' crape myrtle, hard pruning reduces number of flowers and slightly increases flower size.

More details at xrl.us/CRAPEPRUNESTUDY.

Q: What is the best time to feed camellias? I have several that have been planted for more than 15 years.

Maggie Coleman, e-mail

A: Camellias need nutrients when their growth starts in early April. You can use granular synthetic fertilizers then; rainfall will wash them into the soil. However, I see a lot of benefit to feeding camellia, azalea, rhododendron and other woodland shrubs with organic fertilizer. Products such as Holly-tone, Milorganite, cotton seed meal or blood meal contain nutrients that are released over a long period, just as the shallow-rooted plants desire.

Q: My husband put several tablespoonfuls of boric acid on my crown of thorns and a gardenia, trying to kill ants. Now these two houseplants are suffering greatly. Is there anything I can do to rescue them?

Linda Patton, e-mail

A: Boron is an essential nutrient for plants but only in very tiny amounts. Just 1 part per million can be toxic to houseplants. Although boric acid is a fine insecticide, using it as you've described was a bad idea. Boric acid is very soluble in water, so your best bet is to wash the soil from your plant roots and repot them with fresh potting soil. If they continue to decline, discard them. My wife advises that dinner at a nice restaurant always helps her forget boneheaded things I've done to her plants.

Q: We had a kerosene heater malfunction in our greenhouse. Soot covers the plants. What is the safest way to clean them?

Lonnie Ripley, e-mail

A: I'd use soap (not a detergent) on your plant leaves. Soaps include Ivory bar soap and castille soap. Grate some into a bucket of warm water and stir it up. Put cotton socks on both hands and wipe the soot off your plant leaves. Sensitive plants may drop leaves but I expect they will put out new foliage if they were healthy to begin with.

Q: My nephew's Eagle Scout project is to find trees with historical significance during the Colonial period. He is having difficulty finding information on these trees in Georgia.

Ginny Meeker, e-mail

A: Since Georgia had few cities in Colonial times, few trees from that period are recognized for their historical significance. Live oaks were planted in Savannah's Bonaventure Cemetery by Col. John Mullryne prior to the American Revolution. Recently, the city of Dalton planted a "Liberty Tree," a tulip poplar grown from a seed of a Colonial Liberty Tree that grew on the St. John's College campus in Annapolis, Md. For more recent historical trees, the Georgia Urban Forest Council keeps a list at www.gufc.org/registeredtrees.

Listen to Walter Reeves Saturday mornings on NewsTalk 750 WSB-AM from 6 to 10. Call 404-872-0750 to ask questions. His Web site, www.walterreeves.com, contains thousands of answers to lawn and landscape questions. You can buy his autographed gardening books at www.walterreeves.com/books.