November 21, 2004|By Jon Traunfeld and Ellen Nibali | Jon Traunfeld and Ellen Nibali,Special to the Sun
Is it too late to mulch around my shrubs and perennials? Will timing cause problems?
Actually, early, not late, mulching is a problem. Wait until after several killing frosts. Mulch applied too early may retain abnormal warmth in the soil. This can cause new growth to start, resulting in severe damage to the plant. So, mulch away now. Keep the mulch a few inches away from trunks to discourage voles from tunneling to the bark and gnawing on it over the winter. Also, mulch piled on perennial crowns encourages rot, so go lightly there.
I have a red maple in a tree pit in front of my city home. The pit is about 3 feet square. I water it and give it Miracle-Gro plant food in the spring. Last fall the city trimmed dead branches, and now it has three more. I can't see any pest. What could be the problem? I love trees.
Urban trees can suffer from a multitude of stress factors. Receiving limited water dries up and reduces root systems. On the other hand, inferior clay soil does not drain well. When it's saturated, the soil has little space for oxygen, which tree roots need. Too much or too little water would produce symptoms similar to those you describe. The sidewalk and road surface heat up during sunny, hot days. If the tree has a southern exposure, the root system may be too warm for good growth.
Normally, fertilizing mature trees is not necessary, but in this case a slow release fertilizer in the fall would be healthier for the tree (follow label directions carefully). Don't use tree spike fertilizers. A water-soluble nitrogen fertilizer such as Miracle Gro could cause excessive foliage growth without adequate roots to sustain the growth. Another factor affecting urban trees is air pollution. The symptoms you describe could very well be the result of sulfur emissions or other chemical pollutants. Lastly, red maples like acid soil. If the tree is surrounded by concrete, limestone leaching into the root zone will affect the tree's ability to assimilate nutrients. Check our online publication, Fertilizing Ornamental Trees and Shrubs, or request a copy by calling us.
Checklist
1. Dig your hole now if you plan to buy a live Christmas tree to plant after the holidays. Fill the hole with mulch or cover with landscape fabric to prevent soil and water from filling in.
2. Install a stock tank heater in your pond to prevent it from completely freezing over and killing your fish.
Jon Traunfeld, regional specialist, and Ellen Nibali, horticulture consultant, work at the University of Maryland Cooperative Extension's Home and Garden Information Center. The center offers Maryland residents free gardening information and answers to plant and pest questions. Call its hot line at 800-342-2507 (Monday through Friday, 8 a.m.-1 p.m.) or e-mail questions to www.hgic.umd.edu. (You can also download or order publications and diagnose plant problems online.)
