Roses provide a colourful and fragrant focal point for a garden. While most roses are easy to care for, some are susceptible to damage from weather, pests, and disease. These problems can cause the rose's foliage and buds to wither and die.
What To Do First
If a rose's buds or leaves turn brown and dry out they are dead and cannot be saved. It is normal for roses to occasionally have both buds and leaves die. Prune off any dead foliage and buds to 1/4 inch above the closest five-leaf cluster. This prevents rotting, insect infestation and disease. Bag or burn the cuttings to avoid spreading disease or infestation.
Unusually hot and dry weather can kill rose leaves and delicate buds. Increase the frequency and amount of watering you do, and rig some sort of temporary shade for protection.
Botrytis blight -- also known as grey mould -- and powdery mildew can sometimes cause rose leaves and buds to wither and die. Botrytis blight is characterised by a grey mould, while powdery mildew appears as a white, powdery substance. Treat and control both diseases by spraying regularly with a broad-spectrum fungicide.
Several pests can damage and kill both rose leaves and buds. Aphids are tiny green bugs with sticky residue; rose midges are minuscule mosquito-like insects. Japanese beetles are half-inch shiny green or copper-coloured insects. These pests appear on the unopened buds and foliage. Treat with insecticides or insecticidal soaps.