Question From: M. Henleben - MISSOURI
Q: My tall, white hybrid Phlox starts out great every year but just about now, the plant becomes stunted, flower development is blasting and the new leaves are spindly and rolling inward. It seems my Monarda is taking on the same characteristics. No insects in sight, optimal drainage and garden soil. I know what aphids, white fly and spider mites look like, so I'm thinking a soil borne disease or a microscopic pathogen? What do you think?
Sounds like aster yellow to me. Take photos to and independent garden center for an accurate ID. Also Google photos of aster yellows. If your plants have it, sadly they are toast and should be removed, roots and all. Do not plant the same species in that area. Best Nancy and Thank for visiting Yardener.com.
Q: Thank you, you are spot on about the aster yellows. My other question regarding the disease concerns my very large oak leaf hydrangea. I noticed a few branches are showing symptoms. Could I just remove the infected branches and hope for the best? Removing the whole bush would be very difficult. Thanks
Hydrangeas are not affected by aster yellows. See links here: https://extension.psu.edu/catalogsearch/result/?q=hydrangea+diseases for information and ID of hydrangea diseases. Also check out the Missouri Botanical Society website. Best And Happy Yardening, Nancy