What’s wrong with my rhododendron?


I have a large rhododendron that has developed a problem. I believe it has a nutrient deficiency but I don’t know what it is. I had a soil test done on 04/16/2021 (2029) that indicates I need to reduce the pH a half a point. What do you think is the problem?


Rebecca Long, Agriculture and Food System Professional

A picture would be very helpful in starting a diagnosis for your rhododendron. However, I have a sneaking suspicion it may be the same issue that quite a few other people have reported this spring. We have been getting photos of rhododendrons with a range of damage including leaf spots, necrotic edges, and fully dead leaves. Sometimes a large portion of the plant appears dead. Our plant pathologist suspects that the cause may be a combination of abiotic factors (last year’s drought/lack of snowfall/harsh winds) which may have made plants more susceptible to normally mild fungal organisms. She suggests that if it is just a small portion of the plant, to prune out the affected area. If it is a larger portion, you could scrape a small amount of bark off with a knife and see if it’s a white/green color to see if it’s alive. If not, prune down to where it is healthy. This summer, make sure to water the plant through any dry periods (where we get less than an inch of water a week). See this article from Virginia Tech, How And When To Prune Rhododendrons for more info on pruning.