Monty Don, the renowned gardener and host of Gardeners' World, has shared his expert advice on dealing with black spot on roses, a common fungal infection that thrives in warm, humid conditions. As the UK experiences a heatwave, with the hottest May day on record, gardeners may notice dark patches on rose leaves and stems, leading to yellowing and leaf drop.
Don suggests that the approach to black spot depends on personal tolerance. “A lot of plants get black spot, but it doesn't affect the flowering and doesn't affect the health of the plant. It's just unsightly and that, personally, I can tolerate,” he said. However, if a plant is severely defoliated and looks poor while nearby roses are healthy, he recommends removing the susceptible plant entirely.
For widespread black spot, Don advises a practical method: avoid overhead watering to keep leaves dry. “The only practical thing you can do is, don't water overhead. You can't stop the rain, but don't wet the leaves, keep the leaves dry,” he explained on the BBC Gardeners' World Magazine podcast. He also recommends gathering and burning fallen affected leaves, rather than composting them.
Winter care is crucial: “In winter, rake the ground around the plant thoroughly to disturb the spores. Leave it bare over the winter months, then mulch it thickly in early spring.” A cold snap can also help kill spores in the soil. However, Don acknowledges that living with roses means accepting some level of black spot.
