Boxwood: Phytophthora root rot

categories: Boxwood Boxwood Diseases Ornamentals Shrubs

revision date: 2022-11-30 12:00

Phytophthora root rot infecting trunk.
Phytophthora root rot infecting trunk
Photo by: C.R. Foss


Phytophthora is a fungal infection of the roots and crown. Infected plants often show wilting, discolored or dead leaves which remain on the branches, dead twigs and branches, stunting, gradual decline, and premature plant death. Infected roots become watersoaked and rot. Streaking or dark staining may be observed when cuts are made into the wood near the crown of the plant, or cankers may be present on the crown. The fungus persists in the soil and in diseased plant material. Phytophthora prefers high soil moisture.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

  • Plant in well-drained areas.
  • Do not overwater.
  • Do not replant boxwood in areas where it has died previously.
  • Remove and destroy infected plants, including roots where possible.
  • Plant resistant species in infected areas. Your county extension agent or WSU Master Gardeners can make recommendations.

Chemical Management

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

  • None recommended

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