Viburnum Help Please - Ask Extension
Hello - I hope you can help me identify a treatment to save my 13 year old viburnums planted in Mt. Airy MD that have branches of leaves turning brown...
Knowledgebase
Viburnum Help Please #673543
Asked August 06, 2020, 10:36 AM EDT
Hello - I hope you can help me identify a treatment to save my 13 year old viburnums planted in Mt. Airy MD that have branches of leaves turning brown and dropping off, after the leaves drop the branches seem to be dying off. I have examined the plant and did not notice any obvious signs of mildew or insects. I have attached some photos for your reference and would be happy to send more photos if you require them. Thank You in advance for your expert help. John
Carroll County Maryland
Expert Response
Hello John,
This looks like classic damage from a fungal canker disease called Botryosphaeria. Fungicides are not effective but you can trim out all affected branches; look for stems girdled with canker (as in the photo on the page below) and prune below this point into healthy wood. Although this may leave some emptier patches in the branches for awhile, a positive benefit is that the increased air circulation in the shrub's interior may help avoid other issues by promoting faster drying, at least until the growth is gradually replaced. Although the page linked below mentions Rhododendron, this disease affects Viburnum and an array of other shrubs; the mention of partial shade is a bit more Rhododendron-specific, but it can benefit Viburnums as well. Moving a plant this large to a shadier site is impractical, but being aware that full sun can tax their moisture reserves can help you monitor for drought stress in the future.
https://extension.umd.edu/hgic/topics/botryosphaeria-canker-shrubs
Doublefile Viburnums like this one benefit from even soil moisture - they do not prosper in drought and such stresses can make them more vulnerable targets for canker diseases. Occasional irrigation during hot, dry spells would help to preserve their health.
https://extension.umd.edu/hgic/topics/watering-trees-and-shrubs
Miri
This looks like classic damage from a fungal canker disease called Botryosphaeria. Fungicides are not effective but you can trim out all affected branches; look for stems girdled with canker (as in the photo on the page below) and prune below this point into healthy wood. Although this may leave some emptier patches in the branches for awhile, a positive benefit is that the increased air circulation in the shrub's interior may help avoid other issues by promoting faster drying, at least until the growth is gradually replaced. Although the page linked below mentions Rhododendron, this disease affects Viburnum and an array of other shrubs; the mention of partial shade is a bit more Rhododendron-specific, but it can benefit Viburnums as well. Moving a plant this large to a shadier site is impractical, but being aware that full sun can tax their moisture reserves can help you monitor for drought stress in the future.
https://extension.umd.edu/hgic/topics/botryosphaeria-canker-shrubs
Doublefile Viburnums like this one benefit from even soil moisture - they do not prosper in drought and such stresses can make them more vulnerable targets for canker diseases. Occasional irrigation during hot, dry spells would help to preserve their health.
https://extension.umd.edu/hgic/topics/watering-trees-and-shrubs
Miri
