Roses: black spots on canes - Ask Extension
I have over a dozen rose bushes in my yard. All of them proven fairly hardy and disease resistant. However, for the first time, two of them have black...
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Roses: black spots on canes #859094
Asked February 13, 2024, 5:33 PM EST
I have over a dozen rose bushes in my yard. All of them proven fairly hardy and disease resistant. However, for the first time, two of them have black spots on all of their canes.
What do I do?
Clackamas County Oregon
Expert Response
Thank you for your question. There are two known diseases of roses which cause stems to turn black. The first and most common is a fungal disease described here: https://solvepestproblems.oregonstate.edu/plant-problems/roses/black-spot
The second is an insect described here: https://blogs.oregonstate.edu/mgmetro/2017/11/01/rose-stem-girdler-new-pest-caneberries-roses/
I suspect that your rose has the former, but can't see the tissue clearly enough to be certain. I suggest that you submit a plant sample to the OSU Plant Clinic: https://bpp.oregonstate.edu/how-submit-plant-materials
I trust they can provide both a reliable diagnosis as well as treatment. Good luck!
The second is an insect described here: https://blogs.oregonstate.edu/mgmetro/2017/11/01/rose-stem-girdler-new-pest-caneberries-roses/
I suspect that your rose has the former, but can't see the tissue clearly enough to be certain. I suggest that you submit a plant sample to the OSU Plant Clinic: https://bpp.oregonstate.edu/how-submit-plant-materials
I trust they can provide both a reliable diagnosis as well as treatment. Good luck!
