Ninebark fungus - Ask Extension
My common Ninebark is about 7 years old and located in my raingarden. Last year I noticed a fungus was starting on the shrub. I trimmed any affected a...
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Ninebark fungus #831467
Asked May 22, 2023, 6:52 PM EDT
My common Ninebark is about 7 years old and located in my raingarden. Last year I noticed a fungus was starting on the shrub. I trimmed any affected areas. The white fungus has started w a vengeance already. What do I need to do to treat this shrub?
Hennepin County Minnesota
Expert Response
Ninebarks are notorious for harboring powdery mildew. Factors that influence the outcome are:
1. Keeping the shrub pruned for good air flow. Prune during winter. If you prune now it may make it worse.
2. Excess moisture fosters it so you may want to move it to a drier spot.
3. Fungicides can be effective
See the following websites for more details:
1. https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/ninebark/spotsorblotches.html
2. https://extension.umn.edu/plant-diseases/powdery-mildew-trees-and-shrubs
1. Keeping the shrub pruned for good air flow. Prune during winter. If you prune now it may make it worse.
2. Excess moisture fosters it so you may want to move it to a drier spot.
3. Fungicides can be effective
See the following websites for more details:
1. https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/ninebark/spotsorblotches.html
2. https://extension.umn.edu/plant-diseases/powdery-mildew-trees-and-shrubs
