Boxwood Problems - Ask Extension
Hi there,
We recently moved into a house and the two cone boxwoods framing our entryway are starting to turn brown - one significantly on the sides f...
Knowledgebase
Boxwood Problems #702757
Asked July 19, 2020, 4:49 PM EDT
Hi there,
We recently moved into a house and the two cone boxwoods framing our entryway are starting to turn brown - one significantly on the sides facing the house. We have been told that they are around 5 years old and noticed the browning about 2-3 weeks ago. Would love your insights!
Montgomery County Maryland
Expert Response
The boxwood may have been subject to several issues like volutella, a fungal disease (certain cultivars may be more susceptible to this disease), older leafminer (an insect)damage, and possible root problems, etc. A root problem may include site conditions, environmental issues, voles, etc. Below is more information.
Volutella, a fungal disease is managed culturally by pruning out dead areas and all blighted leaves around the plant to lessen the disease load in the area, as well as, pruning to increase airflow for faster drying of leaves. No chemicals are recommended.
https://extension.umd.edu/hgic/topics/volutella-blight-boxwood
Old leafminer damage can be managed by pruning https://extension.umd.edu/hgic/boxwood-leafminer-shrubs
Vole damage - check around the base of the shrubs for vole damage. They are a type of meadow mouse that feeds on the roots of trees shrubs. Remove the mulch and any fallen leaves and check around the base of the plants for silver dollar size holes and look for gnawing on base of stems which can cause dieback. https://extension.umd.edu/hgic/topics/voles
At this point, check for voles. Check the drainage in the area and make sure there are no downspouts dumping water in the root zone. Mulch should be no no thicker than several inches and away from the base of the shrubs. Water the shrubs during dry periods.
Prune out any dead branches and remove old fallen leaves and diseased leaves that have accumulated in the crotches of the branches.
We recommend thinning
(instead of shearing) boxwood to improve air circulation and light penetration. Thinning is a type of pruning that removes interior stems.
Prune out and dispose of the clippings in your trash. Please watch our video which has a demonstration of how to correctly prune and thin boxwoods, https://youtu.be/3i8mcoKapeY
Thinning also will help with management of common fungal diseases of boxwoods.
Visit our website for further information about preventing common pests and diseases of boxwoods.
https://extension.umd.edu/hgic/topics/boxwood-preventing-and-managing-common-pests-and-diseases
Marian
Volutella, a fungal disease is managed culturally by pruning out dead areas and all blighted leaves around the plant to lessen the disease load in the area, as well as, pruning to increase airflow for faster drying of leaves. No chemicals are recommended.
https://extension.umd.edu/hgic/topics/volutella-blight-boxwood
Old leafminer damage can be managed by pruning https://extension.umd.edu/hgic/boxwood-leafminer-shrubs
Vole damage - check around the base of the shrubs for vole damage. They are a type of meadow mouse that feeds on the roots of trees shrubs. Remove the mulch and any fallen leaves and check around the base of the plants for silver dollar size holes and look for gnawing on base of stems which can cause dieback. https://extension.umd.edu/hgic/topics/voles
At this point, check for voles. Check the drainage in the area and make sure there are no downspouts dumping water in the root zone. Mulch should be no no thicker than several inches and away from the base of the shrubs. Water the shrubs during dry periods.
Prune out any dead branches and remove old fallen leaves and diseased leaves that have accumulated in the crotches of the branches.
We recommend thinning
(instead of shearing) boxwood to improve air circulation and light penetration. Thinning is a type of pruning that removes interior stems.
Prune out and dispose of the clippings in your trash. Please watch our video which has a demonstration of how to correctly prune and thin boxwoods, https://youtu.be/3i8mcoKapeY
Thinning also will help with management of common fungal diseases of boxwoods.
Visit our website for further information about preventing common pests and diseases of boxwoods.
https://extension.umd.edu/hgic/topics/boxwood-preventing-and-managing-common-pests-and-diseases
Marian
