Apr 02, Yellow leaves on rose bushes may also be caused by radiant heat. The ground or area below the rose bush is retaining too much heat, which then radiates up into the lower portions of the rose bush. This radiant heat causes heat stress and the lower foliage will turn yellow and fall off as the rose bush tries to protect itself and de-stress. Aug 31, Too little water or stressful conditions, like drought or a heat wave, can cause a rose bush to drop its leaves in an attempt to conserve energy.
Rose diseases that cause leaves to fall off are often signaled by spotting, deformation or other changes in the leaves. Roses are susceptible to fungal diseases, which can cause defoliation. Pests are common causes of leaf drop. Some leaves show the signs of specific pests. Dropped leaves that have notches taken out are due to earwigs or cutworms. Prolonged feeding by. The area probably has too much shade for a full sun plant, but I don't think that is the issue here.
Shortly after planting, its leaves began to develop black splotches and fall off.
The leaves are mostly gone at this point. Oct 16, I have a red climbing rose, 'Rambling Red', which leafs out beautifully in the spring, blooms well with repeat bloom till frost, and doesn't have any black spot. However, after the big June bloom, 90% or more of the leaves simply fall off.
They aren't even yellow, and definitely don't have any black spot. Sawfly larvae chew the upper surface of rose leaves leaving behind the papery, translucent lower leaf surface and the veins.
Heavy defoliation gives plants a brown scorched appearance. Look for sawfly larvae in mid-spring (rose sawflies) or early summer (pear sawflies). Inspect both upper and lower surfaces of the leaves.