Azalea: Leaf and flower gall

• Categories: Azalea Azalea Diseases Ornamentals Shrubs
• Last review date: 2026-02-13 10:07

Biology

The leaf and flower gall fungus attacks expanding leaf and flower buds. Initially, the affected plant part shows a thickening and gradually assumes a fleshy appearance.

Leaves may thicken into fleshy, bladder-shaped galls. The galls are pale green to pink and may later be covered with a white material.

Eventually the leaf galls lose their green or pink color and become brown and hard. Parts of leaves or entire leaves may be affected.

The disease is favored by high humidity and wet leaves. Damage is primarily aesthetic.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

• Avoid overhead watering.
• Space and prune plantings to provide good air circulation.
• Plant varieties which are less susceptible to disease.
• Prune and destroy galls before they turn white to reduce reinfection risks. Prune and destroy any old galls, also.

Chemical Management

• Apply to entire plant before buds break in the spring.
• Repeat 2 to 3 weeks later.

Approved Pesticides

If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.

• Bonide Copper Fungicide Spray or Dust RTU [Organic]
  Active ingredient: basic copper sulfate
  EPA registration number: 4-58
• Monterey Liqui-Cop Copper Fungicidal Garden Spray
  Active ingredient: copper-ammonia complex
  EPA registration number: 54705-7
• Soap-Shield Flowable Liquid Copper Fungicide [Organic]
  Active ingredient: copper octanoate
  EPA registration number: 67702-2-56872
• This list may not include all products registered for this use.