Hi, I'm new here...I've been referring to this website for years though! I have quite a bit of Monarda, but one clump this year that is only on it's 2nd year, the leaves and stems turned yellow and it looked REALLY SAD. Any ideas why?
It could be lacking some nutrients. Give it some compost, I have a small section of my garden that is nitrogen deficient and everything in that area turns yellow each year. If you can't find compost try a good fertilizer.