The clematis and the peony are both showy plants that bloom vibrant and fragrant flowers. The clematis is a long-living, deciduous vine that can live 25 or more years. The peony is a showy, herbaceous perennial with clumping characteristics. Both of these vigorously growing plants are hardy and thrive in warm climates. Although these plants have resilient characteristics, they are both susceptible to several diseases which can be injurious to the plants if left untreated.
Clematis wilt is a fungal disease that can cause sudden collapse and death of the clematis. This disease thrives in the soil and is transported onto the plant by rain and through cross-contamination from pruning and handling. Clematis plants that are infected with this wilt disease will experience nearly immediate death and blackening of flower buds, wilt, vein discoloration and droop. Severely infected clematis will also develop lesions and fungal fruiting bodies. Clematis wilt can be controlled with pruning and fungicidal treatments.
Crown gall is a soil-borne bacterial disease that can thrive for several years in the soil without a host. Clematis is much more susceptible to this disease than the peony. Still, both plants can show fatal results when infected. The bacterium of crown gall infects the plants through open wounds that usually result from pruning and cultivation activities. Plants that are infected with crown gall develop small to large, light colored galls around their soil lines as well as on their stems and roots. These plants will experience growth stunt, dieback and premature defoliation. There is no cure or chemical treatment for crown gall, and infected plants should be removed and destroyed. Avoid planting new vegetation in the same area.
Powdery mildew is a disease that affects both the clematis and the peony. Initially, the disease is cosmetic, attacking the foliage of these flowers. The disease covers the foliage with a powdery white mildew on either side. Progression of the disease causes dieback and growth stunt of the foliage and stems, as the flowers starve from the lack of sunlight and nutrients. Infected flowers are killed by the disease in severe cases. Powdery mildew is easily treated with a fungicidal spray that is designed for the disease, in combination with pruning and cleansing of the foliage.