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

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

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

Approved Pesticides

Examples of pesticides that are legal for home use in Washington State are listed below.
The list may not include all products registered for this use.

• Bonide Copper Fungicide Spray or Dust RTU [Organic]
  Active ingredient: basic copper sulfate (EPA reg. 4-58)
• Monterey Liqui-Cop Copper Fungicidal Garden Spray
  Active ingredient: copper-ammonia complex (EPA reg. 54705-7)
• Soap-Shield Flowable Liquid Copper Fungicide [Organic]
  Active ingredient: copper octanoate (EPA reg. 67702-2-56872)