Last summer my neighbor told me the black spots on my peony were a blight, although my peonies bloomed nicely. What can I do about this?
Your peonies probably have a fungal disease, a common problem. The causes are wet summers with cool damp nights, too much shade, poorly drained soil, or a lack of air circulation. While your neighbor diagnosed your problem as peony blight, which is caused by an air-borne botrytis fungus, the black spots indicate the more common phytophthora blight, according to Walter Schmidtke, nursery manager at Pesche’s Garden Center in DesPlaines.
Early in the spring, young emerging shoots may suddenly wilt and fall over, turn black and show masses of gray-brown botrytis spores. If nothing is done, these spores are carried to developing buds, which turn black.
Black spots on foliage, leaves turning red in summer, and black stripes on the stalk indicate phytophthora. “Plants with these conditions won’t have as much zest” said Schmidtke.
The best protection against recurrence of either blight is good sanitation. In fall, it is important to cut down and throw away all peony foliage, cutting stalks just below the surface of the ground.
If this doesn"t work and you resort to chemicals, the treatment is the same for both diseases. As soon as the shoots emerge in spring, begin spraying with Mancozeb, a copper sulphate solution, and repeat every 7-10 days until buds form, according to University of Illinois Extension. Spray the whole soil area for overwintering spores. In early summer you can spray plants with Daconil, a general purpose fungicide. Cut away any diseased foliage at once.
I have twelve beautiful blooming violet plants on my office desk, placed 12 inches from a light source that’s kept burning day and night. I water them from the bottom and let the water remain in the saucer.
No matter what I spray, I continue to have gnats and other insects in my soil. I also occasionally start to get yellow spots on the tips of the leaves and then the spots start going down the leaves. What’s going on here?
Now that bedding impatiens (I. walleriana) are not recommended because of impatiens downy mildew, what are three good annuals for shade?
At the end of every winter, there are many shrubs growing along sidewalks that are dead and damaged either by salt, wind or dogs. Are there any shrubs that I can plant in these more exposed situations and expect them to survive?