|I have a rose bush that had black spot last year and has it again this year. I bought something for it at a local garden store and I just keep it sprayed. Any suggestions? Thanks.|
|A fungus causes black spot on roses and control requires year round attention. Some cultural practices may be helpful in controlling it. These include planting varieties resistant to it, ensuring your plants are in a location with good air circulation, avoiding wetting the leaves when watering, and cleaning up, removing and destroying any infected leaves. Do this especially well each fall to minimize reinfection from year to year. A clean layer
of organic mulch (such as shredded bark or half finished
compost or chopped leaves) applied before the plants leaf
out again in spring should also help prevent reinfection.
Neem oil may also be helpful. Neem controls aphids and mites on your roses, and the oil version of neem
also will control powdery mildew and black spot.
Some gardeners have had success using baking soda and
water sprays to control black spot. Tests in England
indicated that 1.5 tablespoons of baking soda in 1 quart of
water was effective. Add just a a few drops of dish detergent to help it stick. You may want to try it and see for yourself. Caution: Always test something new like this on a few leaves and wait a few days to see the results before spraying all of your plants.