White Spots on Hibiscus Leaves
Hibiscus plants require cultivated loam and peat soil, direct sunlight and daily watering. While these flowers are already high maintenance, white leaf spots regularly complicate hibiscus growing. White hibiscus leaf spots are a common but serious concern for your plant's health.
Mildew is typically responsible for white spots on hibiscus leaves. Spider mites can also cause white leaf spots. Spider mites sometimes attack hibiscus plants, so do not write off this possible cause, but mites prefer more arid plants, so mildew is the more likely culprit.
Mildew is a fungus that thrives in moist environments. It sucks nutrients out of the plant and gradually kills the hibiscus. Spider mites are microscopic bugs that also feed off the plant's nutrients, slowly killing it.
Mildew presents itself as powdery white spots that grow on the surface of the leaves. Spider mite damage removes pigment from the leaf, creating spots of white, gray or yellow discoloration ingrained in the leaf itself. Spider mites also weave small, whitish webs throughout the plant.
Mildew-damaged leaves should be snipped off at the point where they join the stalk. This usually restores plant health, but the book “Pests and Diseases” recommends applying fungicidal spray to the plant to prevent future mildew growth. Combat mite infestations with pesticides or predatory Phytoseiulus mites.
Grow White Hibiscus
Choose a sunny growing space in which to plant the hibiscus. When planting multiple hibiscus, allow at least 3 feet of space between plants. The National Gardening Association recommends planting in the spring, summer or fall. Place the starter hibiscus in the hole and fill the hole halfway with well-drained soil. Use up to 1 pound of nitrogen per 1,000 square feet of growing space. Spray the plants with horticultural oil or wash with insecticidal soaps, as needed, to remove mites and other insects.
- “Simon and Schuster's Complete Guide to Plants and Flowers”; Frances Perry; 1976
- “Pests and Diseases”; Andrew Halstead and Beatrice Henricot; 2010
- “Garden Pests and Diseases”; Lynne Gilberg and Susan Lang; 1993
- University of California Agriculture and Natural Resources: Hibiscus
- Texas A&M University AgriLife Extension: Tropical Hibiscus (Hibiscus Rosa-Sinensis)
- Clemson Cooperative Extension: Hibiscus
- University of Hawaii at Manoa College of Tropical Agriculture and Human Resources: Hibiscus Waimeae
- National Gardening Association: Improve Soil Fertility With Compost
- National Gardening Association: Hibiscus