# Hibiscus Fungal Diseases
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Leaf Spot
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A common fungal disease, leaf spot disease infects the foliage and stems of the hibiscus. These fungal spores lie dormant on fall debris that lies around the hibiscus and infect the shrub during the cool, rainy periods of spring. The infected hibiscus leaves develop tiny, brown-colored spots that develop into larger, decaying areas. Severely infected hibiscus shrubs experience heavy defoliation, which often results in stunted growth and dieback.
Powdery Mildew
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Powdery mildew spores are most infectious during the warm, dry periods of spring and early summer. These airborne spores infect the surfaces of the hibiscus leaves. The infection develops tiny fungal spores on the foliage, which are concealed by layers of white, powdery mildew. Initial powdery mildew infections cause only cosmetic injury. However, continued and severe powdery mildew infections cause the hibiscus foliage to discolor, curl and wilt as the shrub experiences dieback and stunted growth. The hibiscus shrub’s blooms can also become infected, resulting in discolored and distorted blooms, as well as failed buds.
Rot
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Phytophthora root rot is a soilborne disease that favors high humidity levels and continuously wet soil. This rot disease enters the hibiscus shrub through its roots and infects its vascular system. The infected vascular system becomes unable to successfully pass nutrients and water throughout the hibiscus, resulting in a progressive breakdown of the plant. The hibiscus shrub’s foliage experiences wilt and defoliation, while the stems and woody areas become weak and brittle.
Considerations
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Timely care and maintenance greatly reduces the hibiscus shrub’s potential for fungal infections. Keep the hibiscus shrub’s planting area free of debris and remove weeds as they appear. Treat the hibiscus with fungicidal treatments regularly throughout the growing season to reduce spore development. Water the hibiscus regularly to maintain a moist, but not saturated, soil environment. Allow the hibiscus’ soil to dry slightly, but never completely, between waterings to prevent overwatering and potential rotting infection. Feed your hibiscus in the early spring and after each flush of summer growth with a slow-release fertilizer, such as a 15-5-10 or 15-5-15 combination. Always apply the feed according to the package’s directions to prevent injury to the root system.
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