A: If your tree hasn’t been fed in a while, I don’t have a problem with fertilizing, even in winter. Unlike annual and perennial flowers, which have shallow, compact root systems, tree roots are spread widely beyond the drip line. Applying fertilizer months before the spring growing season allows nutrients to wash into the soil and disperse in all directions. A nutrient ratio of 4-1-2 or 4-1-1 is excellent for trees. After this feeding, a trained arborist can evaluate how it has affected the trees’ shoot growth and can advise on whether another fertilizer application is warranted.
Q: My 25-year-old boxwoods have been slowly dying, one branch at a time, for three years. I’ve treated them with insecticide and disease control, with no noticeable difference. — Marsha Royal, Upson County
A: In my experience, boxwoods are more likely to be affected by poor root systems than by insects or disease. Make sure water does not sit on or flow across the roots. On the other hand, make sure the shrubs are watered weekly in the heat of summer. The fibrous roots are greatly benefited by a 1/8-inch layer of cottonseed meal spread from the trunk outward in all directions and covered with a layer of straw or mulch. The meal feeds the shrub slowly while the mulch protects roots from summer heat and drought.
Q: I’ve heard that nothing will grow where shells from pistachio nuts were thrown. — Hugh Waddy, Jonesboro
A: I can’t find any confirmation for what you heard. It’s true that black walnut roots, wood and shells inhibit the growth of some (but not all) plants nearby. Some folks are very allergic to raw pistachio and cashew nut meats. My guess is that information about pistachio allergens got mixed up with pistachio allelopathy, resulting in the rumor you heard.
Listen to Walter Reeves from 6 to 10 a.m. Saturdays on AM 750 and now 95.5FM News/Talk WSB. Go to www .gardeningingeorgia.com for details on his TV show, visit www.walterreeves.com or join his Facebook Fan Page at xrl.us/wrfacebook for more garden tips.