Trees/Old dogwood dropping leaves
Earlier this year I posted a question about this spectacular old dogwood of ours which stands about 20ft high, and for the first time since we have lived in this house (18 yrs) it hardly bloomed this spring, also it had grown little water sprouts along the branches so I wondered what was happening. The advice I got was to leave the water sprouts, the tree was regenerating. So the sprouts were left and the tree flourished as never before! The leaves have been big and lush like velvet, it has looked absolutely beautiful and VERY healthy. Now, today I was in the garden looking and it has suddenly shed lots of leaves, bright green healthy looking leaves. I rushed in to ask my husband if he had done anything to the tree but he said he had never been near it. He came down got hold of a branch and shook it gently the leaves just showered down. What's happening? Can you help please?
Sounds like dogwood anthracnose. here is a web link to informatio on this disease. http://na.fs.fed.us/spfo/pubs/howtos/ht_dogwd/ht_dog.htm
In Alabama Dogwoods in the Northern part of the state are being infected with this disease. Usually associated with higher elevations like near Huntsville, Fort Payne, and Scottsboro and the surrounding counties.
No single practice can insure complete control of dogwood anthracnose. Successful management of dogwood anthracnose involves a combination of both cultural and chemical control measures as outlined below. In some instances total destruction of infected trees may be more economical and more prudent in protecting other non-infected dogwoods. Trees with extensive twig dieback and/or trunk cankers should be destroyed because effective control is not possible.
A healthy vigorous dogwood is better able to withstand infection from anthracnose than a weakened tree growing under stress conditions. Maintain tree health through proper watering, mulching, and fertilization. Water during drought periods, but do not use overhead irrigation since this may increase the potential for disease infection and spread. Mulching to a depth of 2-4 inches can help maintain uniform soil moisture as well as help protect trunks from mechanical injury; however, be sure to keep the mulch away from the tree trunk. Fertilize as needed, using a balanced fertilizer with fairly low nitrogen content for moderate growth. Use 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. Rapidly growing, succulent twigs which have been stimulated by excessive fertility are more susceptible to anthracnose infection.
Good sanitation is especially important for trees infected with anthracnose. Prune out and destroy dead and dying twigs and branches and rake up fallen leaves to help reduce potential sources of inoculum and improve tree appearance. It is also advisable to prune out water sprouts which develop on the trunk or main scaffolding limbs since they are very susceptible to infection from anthracnose. Prune only under dry conditions and sterilize pruners with alcohol between pruning cuts.
Avoid planting monocultures of flowering dogwood, Cornus florida. There are no flowering dogwood cultivars known to be resistant to dogwood anthracnose. Kousa dogwood, C. kousa, (also known as Chinese or Japanese dogwood# is resistant but not immune to anthracnose: however it may be a better choice for replanting in sites where flowering dogwoods have died from the disease.
Fungicide sprays are recommended only if you live in a high risk area for anthracnose or if your tree has been confined as being infected with anthracnose. Start sprays at bud break and continue spraying according to label directions. The recommended interval between sprays will vary depending on the fungicide and the rate of application. Recommended fungicides include: myclobutanil #trade name Immunox#; propiconazole #trade name, Banner# and chlorothalonil #trade name, Daconil 2787). Make sure the fungicide you use has dogwood listed on the label. Follow all label instructions regarding amounts of pesticide to use, method of application and safety warnings.