+22 Missouri Botanic Garden Black Spot Roses Ideas. This defoliation, if severe, will weaken the plant, reduce flowering, and make the plant more subject to winter damage. Triforine breaks down rapidly in the environment.
The fungal spores need a wet surface to germinate and cause infection. Examine shrubs for winter injury. This defoliation, if severe, will weaken the plant, reduce flowering, and make the plant more subject to winter damage.
