Black Spot is a devastating fungal disease that most commonly infects roses. You can identify Black Spot by the round, black spots – with fringed, often yellow, margins that appear on the leaves. The spots begin on the upper sides of the foliage, gradually turning the leaves yellow before dropping. The spots can be as large as a ½ inch in diameter. Spots can also form on stems, and plants can be completely defoliated. Black Spot is most common in warm, humid weather with frequent rain.
- Plant resistant rose varieties.
- Avoid overhead watering and prolonged wet foliage.
- Prune to keep the center of plants open for good air circulation.
- Clean up and dispose of (not in the compost pile) fallen leaves and prunings in winter. Remove infected leaves as soon as you notice them.