Spring showers exacerbate the condition of fungal diseases such as Anthracnose. Anthracnose is a disease that deeply affects Dogwood populations; in fact, this disease has destroyed a large portion of the native Dogwoods in United States forests. It affects every part of the host tree that is above ground: leaves, flowers, new shoots, bark, fruits, and seeds.
How Does it Affect My Plants?
During the middle of May and into June, blotches with a tan center and a purple/reddish margin will appear on the underside of the leaf; tiny black or brown spots may appear beneath the blotches as well. The flower “petals” will begin to show reddish/brown patches and, in some cases, entire leaves will become infected and die. These black/brown spots may also produce spores (which can be carried by rain, insects, and birds) in late Spring; these spores ooze out in slimy beige clusters.
Once the entire leaf has become infected, tan depressions (or cankers) will appear. This will produce the same tiny black or brown spots as are on the undersides of the leaves. Over time, the infection of twigs and shoots will kill the branch, starting at the bottom and moving upwards. In response to its loss of leaves, the tree may attempt to produce new shoots, but the fungus will easily affect them as well. Once sprouts are infected, the fungus moves quickly into the trunk, and severe cankers will split and buckle the bark.
What Can Be Done?
Affected trees in shady locations generally die within 13 years. Others in more sun-exposed areas often survive but show varying degrees of severity from year to year. Healthy trees are better able to cope with Anthracnose, so one important thing is to keep your trees stress free.
Our arborists are like tree doctors; they know all about fertilization, pruning, and fungicides that can keep your plants healthy and Anthracnose-free. Give us a call to set up an appointment with one of our certified sales arborists so they can assess and diagnose the trees and shrubs on your property. The sooner the better!