rhododendron has green blotches
My rhododendron has green blotches on the main branches. Does that mean it can't be saved? The leaves are looking unhealthy. My favorite shop owner told me to trim it way back.
The green blotches on your rhododendron could be lichen but without a photograph I can not be certain. Lichen won't harm a rhododendron but its presence on your plant could signify another problem. It could be that your rhododendron sustained winter injury and shed a bunch of leaves. This leaf loss then opened up your rhododendron to more light which fostered the growth of the lichen.
At this time, prune only those branches that are broken or surely dead. If you are in doubt when pruning, do a scratch test (scrape the outer bark and see if you have a green layer underneath). If you see green, do not remove the branch. More extensive pruning should be reserved until after new growth begins, which usually happens in May and June. At this time the extent of the winter damage will be more obvious to you.
In the meantime I would recommend feeding your rhododendron a half dose of acidic fertilizer and watering it to encourage new growth.
For information on how to prune rhododendrons, please visit the following link: