Roses with spots
I have about six rose bushes in my yard. This one is located far from the others next to my raspberries. I recently bought this house so I have no details what type of rose it is. Last year they were spotted and grew poorly. This year there seems to be more of them but they are SUPER thorny and spotted again. Can I fix this? Thank you!
Clackamas County Oregon
Thank you for your question. Roses have their challenges, and the closest I can come without an exam under a microscope is botrytis blight, which is discussed on page 4 in this Extension article: http://cru.cahe.wsu.edu/CEPublications/FS246/FS246E.pdf There is no ‘fix’ other than that discussed above (pruning to remove diseased petals and removing dropped tissue to slow down the disease). Here is another Extension guide to care of rose bushes (Washington environment is the same as Oregon): http://cru.cahe.wsu.edu/CEPublications/FS164E/FS164E.pdf If you would like to have some tissue examined for signs of a fungus, bring some samples to the Extension office at 200 Warner Milne Road, Oregon City, between 9 and noon, and 1:00 and 4:00 pm on weekdays. Good luck!
BTW, you also mentioned their thorniness. Although I can see nothing in the photos, one other (rather rare to Oregon) disease is described here: https://www.canr.msu.edu/news/rose_gardeners_should_learn_the_symptoms_of_rose_rosette_virus If you see any of these symptoms as well, bring in a stem to be examined as well.