Time to act:
Jun, Jul, Aug, Mar, Apr, May
Leaves and sometimes stems are marked by dark blotches caused by a fungus. The spores overwinter on fallen leaves, stem lesions and bud scales, and reinfect the plant the next spring when there's a flush of new foliage. If these leaves are then infected, they too eventually turn yellow and drop. If not dealt with, the plant will weaken.
Rose black spot is very similar and can be dealt with in the same way.
Leaves are marked with purple or brownish-black spots, then turn yellow and fall. Smaller marks sometimes also blotch the stems. Plants can be weakened by regular attacks.
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