How to save large rosemary bush - Ask Extension
We have two large rosemary bushes near the entrance of our building in downtown Portland. They are well established and have been in place for decade....
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How to save large rosemary bush #791246
Asked May 17, 2022, 12:47 PM EDT
We have two large rosemary bushes near the entrance of our building in downtown Portland. They are well established and have been in place for decade. This winter one started browning/dying on the sidewalk edge and over the past few months this has greatly extended. What to do? It seems like a disease which is spreading. Shall I cut out the brown part?
Thank you.
Maria
Multnomah County Oregon
Expert Response
Thank you for your question, Maria. There are two diseases which cause this in rosemary plants, both helped by bad drainage in the soil. https://pnwhandbooks.org/plantdisease/host-disease/rosemary-rosmarinus-officinalis-botrytis-stem-canker
and https://pnwhandbooks.org/plantdisease/host-disease/rosemary-rosmarinus-officinalis-root-rot
We cannot identify which disease the plant has just from photos. You can have plant tissue examined for an accurate diagnosis, but, if the soil is uniformly damp, you may not want to keep the plant. Here is the contact information for the OSU Plant Disease Clinic: https://bpp.oregonstate.edu/plant-clinic/submit-sample/how-submit-plant-materials
Good luck!
and https://pnwhandbooks.org/plantdisease/host-disease/rosemary-rosmarinus-officinalis-root-rot
We cannot identify which disease the plant has just from photos. You can have plant tissue examined for an accurate diagnosis, but, if the soil is uniformly damp, you may not want to keep the plant. Here is the contact information for the OSU Plant Disease Clinic: https://bpp.oregonstate.edu/plant-clinic/submit-sample/how-submit-plant-materials
Good luck!
