Hi I live in Ma, every summer my rhododendrons are covered in aphids !?! I use neem oil spray each leave and try to keep on it . Even after they bloom the new growth always is infested with bugs .. so I prune the new growth because I don’t want to take the chance of making the bugs worse !! So on top of the aphids problem I never get the Bush to grow ?? Could you recommend anything to help me with this ongoing issue, thank you
Plymouth County Massachusetts
I would not recommend pruning the new growth, which is why the plant is not thriving. Aphids normally attack the new growth on rhododendrons so it is important to keep an eye out for them early in the growing season, which it sounds like you are doing. And, as you also point out, you have to stay on top of them. In addition to or in lieu of the Neem oil, a regular high pressure spray of water will also knock the aphids off of the leaves, so you might want to try that.
The attached article from the Univ. of Minnesota offers a few suggestions to try to control the aphid population, such as controlling weeds, companion planting (plants that may draw the aphids from the rhododendron) and beneficial insects.
Yes, aphids are pests, but for the most part, they will not do any serious damage to a rhododendron.
I hope this is helpful information and please feel free to write back with additional concerns or questions.