Diseases Affecting Boxwoods: An Overview

Boxwood is a popular evergreen plant used in landscaping, hedges, and topiary. However, while it is known for its beauty, boxwood plants are susceptible to various diseases that can cause serious damage if left untreated. In this article, we will discuss some of the common diseases affecting boxwoods, their symptoms, and how to prevent and treat them.

Blight Diseases

Blight diseases are caused by fungi and can affect boxwoods at any time of the year. The most common blight diseases affecting boxwoods are Volutella blight and Boxwood blight.

Volutella blight causes orange-brown spots on leaves, stems, and branches. These spots can enlarge and kill the affected parts of the plant. To prevent and treat Volutella blight, prune affected areas, avoid overhead watering, and use fungicides.

Boxwood blight is a highly contagious disease that spreads quickly and can cause complete defoliation of the plant. Symptoms include brown spots or lesions on leaves, black streaks on stems, and leaf drop. To prevent and control Boxwood blight, maintain good sanitation practices, remove infected plants, and use fungicides.

Leaf Spot Diseases

Leaf spot diseases are caused by fungi and can affect boxwoods during periods of high humidity or wet weather. The most common leaf spot diseases affecting boxwoods are Macrophoma leaf spot and Phyllosticta leaf spot.

Macrophoma leaf spot causes circular brown spots on leaves that may have yellow halos. Infected leaves may drop prematurely. To prevent and treat Macrophoma leaf spot, remove fallen leaves, avoid overhead watering, and use fungicides.

Phyllosticta leaf spot causes dark brown spots on leaves that may have yellow halos. Infected leaves may also drop prematurely. To prevent and treat Phyllosticta leaf spot, remove fallen leaves, avoid overhead watering, and use fungicides.

Root Rot Diseases

Root rot diseases are caused by fungi and can affect boxwoods when soil drainage is poor, or the plant is overwatered. The most common root rot diseases affecting boxwoods are Phytophthora root rot and Pythium root rot.

Phytophthora root rot causes yellowing and wilting of leaves, stunted growth, and eventual death of the plant. To prevent and control Phytophthora root rot, improve soil drainage, avoid overwatering, and use fungicides.

Pythium root rot causes yellowing and wilting of leaves, stunted growth, and root decay. The roots of the infected plant will appear black and mushy. To prevent and treat Pythium root rot, improve soil drainage, avoid overwatering, and use fungicides.

Nematode Diseases

Nematodes are microscopic worms that can cause serious damage to boxwoods. They feed on the roots of the plant, which can lead to stunted growth, yellowing leaves, and eventual death. The most common nematode affecting boxwoods is the Root knot nematode.

To prevent and control nematode infestations, improve soil drainage, avoid over-fertilizing, and use nematode-resistant cultivars. If nematodes are already present, remove and destroy infected plants and soil.


Boxwoods are beautiful plants that require proper care and maintenance to thrive. By understanding the common diseases affecting boxwoods and how to prevent and treat them, you can keep your plants healthy and beautiful for years to come.

boxwood diseases, boxwood blight, volutella blight, macrophoma leaf spot, phyllosticta leaf spot, phytophthora root rot, pythium root rot, nematodes

Volutella blight on boxwood

Boxwood blight on leaves

Phytophthora root rot on boxwood