It's fall and local jurisdictions are getting ready to remove leaves. So it's the perfect time for me to share my six principles for clearing fall debris and maintaining planting beds in winter.
* Clean up. Leaves covering the lawn will suffocate it, so they should be raked and put into the compost pile. Debris should also be cleared away from shrubs that flower in winter or early spring, but only if it's suffocating them or destroying their ornamental value. And always dispose of leaves and dead branches from around plants that have disease problems.
Discarding diseased foliage should be your first priority. Put it in trash bags for disposal. Perennials that qualify for disposal are those whose foliage displayed mildew or wilt problems from spring and summer fungus; they are frequently phloxes, primroses and peonies. Also eliminate vegetables in the nightshade family, such as tomatoes and peppers, and cruciferous ones, such as broccoli, cauliflower and cabbage, plus any vegetables that displayed disease or insect problems.
Get rid of woody shrubs, or branches from them, that died from fungus or root rot diseases. Candidates for disposal are azaleas, dogwoods and rhododendrons. The symptom to look for on these woody plants is an entire branch of leaves wilting quickly and dying while the rest of the plant appears healthy. If you are unsure whether the damage was caused by a disease or insects, contact the local Cooperative Extension Service.
Another excellent fix for fungus is to promote efficient air circulation between the plants. Breezes blowing through a garden dry foliage quickly, which is an especially good way to control leaf-spot diseases. The time to promote air circulation is when you are designing and planting your garden.
* Cut down. The next step is to cut down the perennials as they freeze back. Using a string trimmer, hand sickle, hedge trimmer, lawn mower or hand pruner, cut the top growth of perennials into as many pieces as possible. Allow a one- to two-inch stubble from each plant to stick out of the ground. This will help you remember where it is, so you can keep leaves and chopped perennials in place and away from the plant. Let the debris lie where you made it. It's nutritious.
* Condition. After problem plants have been discarded and everything else cut down, mix in the organic material, such as plant leaves and partially decomposed bark mulch that has been on the soil surface during the past growing season, and whatever compost you have made since spring. Hoe or cultivate these materials a minimum of two to four inches into the soil between your plantings. The deeper the better. Improving soil drainage and aeration with organic material is known to reduce populations of soil-borne pathogens.
* Cover. Now go to the groundcovers and the plants where stems can't be lifted. Using a shovel, a pitch fork or your hands, place organic material wherever you can.
When leaves and small stems drop to the ground and decay, the plant debris makes an excellent fertilizer. This material includes such things as grass trimmings on lawns and needles under conifers. In a natural setting, you can let the leaves lie if they're not covering plants that flower in the winter and early spring. Dry leaves laid over flower beds will also insulate and protect early-spring plants over the winter, as long as the leaves are removed when necessary for plants to perform well.
You can reduce huge accumulations of leaves and sticks to a fine consistency using a chipper shredder, which is available where outdoor tools and power equipment are rented or sold. If you chip sticks and shred leaves, you can mulch your beds with the material for winter protection. Then you can spread a thin layer of ornamental bark right over top in spring without having to do further cleanup. You might also chip and shred the material going into your compost pile. It will decompose much faster as small particles.
* Dispose. Diseased material should be put out with the trash. You can put excess leaves and other debris out for collection by the county or municipality. Many jurisdictions grind and partially compost leaves, which are then made available to residents in springtime. Call your county or city department of water, sewer and street maintenance to learn whether they collect them at your location.
* Protect. The main cause of winter kill is desiccation from the drying winter winds coupled with a lack of available soil moisture in below-freezing temperatures. Before blustery winds freeze the soil surface, take one last step to protect such tender shrubs as camellias, loropetalums, figs and roses.
Roses and figs can be completely buried in topsoil or mulch, canes and all, for the greatest degree of protection. You simply uncover or dig out the plant stems in late winter prior to growth.
When temperatures fall to an average of 30 to 35 degrees Fahrenheit, hammer several 2-by-2-inch stakes into the ground, cutting them to be one to two feet taller than the plants you wish to protect. Wrap burlap around the stakes to screen the plants from winter winds. Use tacks or a staple gun to attach the fabric. Don't cover the top with burlap, but you can take dry leaves from your shade trees and fill the burlap bin you created. Do it by mid-December. Remove burlap and clean out the leaves before growth begins in spring.
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is firstname.lastname@example.org.