Roses, beloved for their elegance and variety, are susceptible to black spot, a fungal disease that causes purple or black patches on leaves. Recognised as the 'most serious' disease for roses, it can weaken plants over time, making them vulnerable to other infections and harsh winters.
Gardeners have shared simple household remedies to combat black spot. One enthusiast reported success with tea and coffee bags emptied around the base of roses, noting no black spot appeared that year. Experts from The Spruce confirm that coffee grounds, rich in nitrogen, can improve soil quality and deter diseases like Fusarium wilt, while tea leaves provide tannic acid as an effective fertiliser.
For those who prefer an alternative, baking soda spray is recommended. Mix one teaspoon of baking soda in one cup of warm water, add up to one teaspoon of liquid soap, and spray rose leaves thoroughly every couple of days. This solution also helps prevent powdery mildew, another common fungal issue.
Black spot spreads easily, so pruning affected leaves is crucial. Dispose of them immediately and avoid leaving them in the garden. The disease thrives in damp, humid conditions, making summer the peak season for outbreaks. While it rarely kills roses in the first year or two, persistent infections can weaken plants significantly.
