|What do you suggest I do for my peony that has done well for several years, but now has curled leaves and black spots. I've tried fungicides and Sevin spray. Didn't help.|
|It is very difficult to stop any disease in the season it appears. Fungicides help protect plants from disease; however, they are not very effective at "curing" a problem once it has started.
The best method of limiting disease from year to year is to cut off, remove and destroy all peony foliage every fall after frost. You may also wish to cut off, remove and destroy all the blackened plant parts when they show up; dip your pruners into a disinfectant (1 part household bleach and 9 parts water) solution as you cut to avoid spreading any disease to uninfected parts.
Just for the record, fungicides will help protect uninfected plant parts; Sevin is a pesticide and won't do a thing to help your peony recover from a fungal disease.
Next spring you may want to use a preventative application of fungicide just as the leaves are emerging to help protect them from developing the same problem next year.