Question: What are those dark brown spots all over my rose leaves? The leaves turn yellow and fall off, and the plants don’t seem to be very vigorous either.
Answer: That’s black spot, the number one problem of roses world-wide. It’s a fungal leaf spot that defoliates many varieties of roses, some worse than others. It spreads most quickly in high humidity and where air circulation is poor. Avoid overhead irrigation whenever possible, and spray the plants weekly with a properly labeled fungicide. You’ll need to spray from early spring into the summer and in the fall. If the problem persists in the summer, spray then as well, but don’t ever spray roses when the sun is hitting their foliage if temperatures are above 85 degrees. If you replace these susceptible roses, look at the EarthKind® selections that have been identified by Texas A&M as being highly resistant to black spot and other problems.