I planted 5 rhododendron bushes and the new leaves are turning brown.
What Causes Rhododendron Leaves to Turn Brown?
Certified GKH Gardening Expert
Since they are newly planted, I would have to say it sounds like a watering issue. It is possible that there are air pockets in the soil, that are affecting the roots and preventing them from taking up water. I would water the area generously and then step firmly on the soil around the plants to help collapse any air pockets.