Rose black spot
Rounded black blotches with a diffuse fringed edge on rose leaves, usually with yellowing spreading out from them, followed by early leaf fall. It is specific to roses — the commonest fungal disease of the genus in Britain — and is not the explanation for a dark spot on anything else.
Caused by: Diplocarpon rosae · also called black spot
What brings it on
Warm wet weather, and leaves that stay wet for several hours. The fungus overwinters on fallen leaves and on the stems, so an infected bush reinfects itself the following spring.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Rose black spot
Checked 2026-08-13
Usually seen: May, June, July, August, September
Preventing it
Ordered by how much difference each measure actually makes, not by how often it is repeated.
- Clear and destroy fallen leaves in autumn, and prune to keep the centre of the bush open so foliage dries quickly. Both interrupt the cycle that makes the disease recur in the same plant each year.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Rose black spot — prevention
Checked 2026-08-13
- Choose cultivars with recorded black spot resistance where you are replanting. Resistance varies widely and is the most durable measure available to a home gardener.
source
Sourced guidancemoderate confidence
- Royal Horticultural Society: Rose black spot — resistance
Checked 2026-08-13
Dealing with it once it is there
- Remove affected leaves as they appear and avoid overhead watering. Any fungicide must be approved for ornamental roses and used strictly as the label directs — the label is the legally binding instruction and takes precedence over any general advice.
source
Sourced guidancemoderate confidence
- Royal Horticultural Society: Rose black spot — control
Checked 2026-08-13
What it affects
Signs that lead here
Each of these lists the other things that produce the same sign, and how to tell them apart.
On sprays and treatments
GrowingHQ does not tell anyone what to apply, at what rate, or how often. Pesticide approvals differ by country, change without notice, and the product label is legally binding — it is also the document you are holding. What is described here is cultural and physical control, which is what a home grower can act on without a label in front of them.
Plant-specific guides
Where this is one of several causes that look alike on a particular plant, GrowingHQ publishes the differential rather than the general answer.