Rhododendron: Physiological leaf spot

categories: Ornamentals Rhododendron Rhododendron Diseases Shrubs

revision date: 2022-12-05 12:00

Rhododendron physiological leaf spot.
Rhododendron physiological leaf spot
Photo by: R.S. Byther


Rhododendron leaves sometimes develop variously-sized and -shaped spots. These are usually dark purple in color. The exact cause is unknown, but cultural or environmental stress may result in physiological leaf spot. One particularly susceptible variety is the rhododendron Mrs. G.W. Leak. This problem does not usually cause any permanent harm to the plant.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Provide proper culture for the plants, especially proper watering and fertilization.
  • Plant less-susceptible varieties in highly visible locations where physiological leaf spot would be an aesthetic problem.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • None recommended