Hibiscus Tree Leaf Spots & Diseases

Leaf Spot

• Leaf spot is a spore-borne disease that has positioned itself as one of the hibiscus’ most common ailments. This fungal disease infects the foliage and stems of the hibiscus, causing light-colored spots and lesions across the surface of the infected foliage. Although unattractive, this fungal disease causes only minor injuries to the foliage and does not affect the overall state of the healthy hibiscus. Infected foliage can be trimmed from the tree or simply allowed to defoliate. Fungicidal treatments are effective but are not necessary.

Bacterial Leaf Spot

• Bacterial leaf spot is an aggressive disease that infects the hibiscus tree’s foliage, stems and blooms. A spore-borne disease, bacterial leaf spot causes brown spots and lesions on the infected surfaces that are pronounced with yellow halos. The spots decay with age causing a “gunshot” appearance. The infected hibiscus experiences dieback and takes on a blighted appearance. Severe bacterial leaf spot infections may also cause deterioration of the root system and vascular system when the infection enters lower parts of the tree. Chemical treatments are helpful when combined with pruning and proper care.

Gray Mold

• A destructive disease, botrytis blight, or gray mold, infects the hibiscus tree’s soft tissue areas, including its blooms and new growth. The infectious fungal spores create small, gray-colored spots on the infected tissue. The spots quickly develop into gray coverings of mold that decays the infected hibiscus tissue. In severe cases, the infection weakens the overall health of the tree, causing growing stunt and dieback.

Verticillium Wilt

• Verticillium wilt is a deadly disease that can thrive for years in the soil without a host. This fungal disease infects the hibiscus tree through its root system, deteriorating the tree from the ground up. The disease causes a gradual decay of the hibiscus tree’s vascular system which prevents it from properly passing water and nutrients throughout the tree. The infected hibiscus experiences wilt, dieback and growth stunt. Symptoms often appear sporadically throughout the tree until the entire tree is infected. Verticillium wilt has no cure and severely infected hibiscus trees should be removed and destroyed.

Prevention and Treatment

• The hibiscus tree that receives proper care and maintenance is better able to defend itself from serious diseases. Plant the hibiscus in a disease-free area to avoid verticillium wilt and other soil-borne infections. Choose a well-drained area with a nutrient-rich, loamy soil environment. Keep the hibiscus tree’s area free of debris and defoliation as infectious spores often take shelter in this debris just before infecting the tree. Irrigate the hibiscus tree regularly throughout the growing season to maintain a slightly moist soil environment, and feed it regularly to replenish it nutrients. Treat the infected hibiscus immediately to prevent severe infections and permanent injury. Always prune away the infected blooms, foliage and branches to prevent the spread of disease throughout the tree.