Boxwood Diseases: Identification and Treatment
Boxwoods are popular evergreen shrubs often used for decorative edging around gardens and homes. However, they are susceptible to several diseases that can affect their health and appearance.
Identifying Boxwood Diseases
Decline
Decline is a mysterious disease that causes boxwoods to exhibit various symptoms, including yellowing and dropping leaves, random branch dieback, and sunken cankers on the wood and root crowns. To reduce the risk of decline, remove dead branches and leaves to improve air circulation. Avoid overwatering during the summer and provide adequate water before frost to help the plant survive the winter. If decline occurs, do not plant new boxwoods in the same location.
Root Rot
Root rot causes the leaves of boxwoods to turn pale and the roots to darken and rot. Unfortunately, there is no effective treatment for root rot, and it will eventually kill the plant. To prevent root rot, plant resistant boxwood varieties in well-drained soil and water sparingly.
Boxwood Blight
Boxwood blight causes leaves to develop brown spots and may cause them to drop. It also forms cankers on the wood and, in wet conditions, produces white fungus. To treat boxwood blight, cut away and dispose of affected branches and leaves. Apply new mulch to prevent spores from splashing up from the soil and use a fungicide to control the spread of the disease.
Nematodes
Nematodes are microscopic worms that feed on the roots of boxwoods. While they cannot be eradicated, regular watering, mulching, and fertilizing can help keep them in check.
Volutella Canker
Volutella canker, also known as Volutella blight, causes leaves to turn yellow and die. It can also kill stems and produce masses of pink spores in wet conditions. To treat Volutella canker, prune back dead material to improve air circulation and apply a fungicide to control the spread of the disease.
Treatment Options for Boxwood Diseases
Cultural Practices
- Improve air circulation by removing dead branches and leaves.
- Avoid overwatering, especially during the summer.
- Water deeply before frost to help the plant survive the winter.
- Plant resistant boxwood varieties.
- Use well-drained soil to prevent root rot.
- Apply mulch to suppress weeds and prevent spores from splashing up from the soil.
Chemical Control
- Use fungicides to control the spread of boxwood blight and Volutella canker.
- There is no effective chemical treatment for root rot.
Prevention is Key
The best way to manage boxwood diseases is to prevent them from occurring in the first place. By following these preventive measures, you can help keep your boxwoods healthy and thriving:
- Choose resistant boxwood varieties.
- Plant in well-drained soil.
- Avoid overwatering.
- Prune regularly to improve air circulation.
- Remove dead leaves and branches.
- Apply mulch to suppress weeds and prevent spores from splashing up from the soil.
- Inspect your boxwoods regularly for signs of disease.
By following these tips, you can help prevent and treat boxwood diseases, ensuring that your prized shrubs remain healthy and beautiful for years to come.
