Boxwood: Leaf spot
categories: Boxwood Boxwood Diseases Ornamentals Shrubs
last review date: 2026-03-15 12:35
Photo by: R.S. Byther
Biology
Boxwood leaf spot is caused by fungi which survive in fallen, diseased leaves beneath the plant.
Leaves develop discolored spots and may turn tan or brown from the margins and tips inward.
Small, black fruiting bodies of the fungus often appear on the discolored spots or the underside of the leaves.
Leaf spot is favored by wet, humid weather and damp planting conditions.
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!
- Prune and destroy infected and dead plant parts.
- Collect and destroy dead leaves under plants and in branch crotches.
- To reduce likelihood of infection, avoid overhead watering and space plants to provide good air circulation.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- Make fungicide applications in spring before new growth starts.
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.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.