u/Venus-crytrap

I transplanted a rhododendron a neighbor did not want last Fall in my yard. This Spring I’ve noticed the extent of the leaf spot infection and some other dead branches to prune out.

I don’t want to stress it out more after transplanting and now flowering, when is a good time?

And from what I’ve read I should remove ALL the infected leaves, yes?

MN zone 4b

Thank you