Dying Pieris japonica
I have more bushes dying in my yard (skip laurels before). Now some well established Pieris japonica bushes are going south. They have been doing well for over 7 years, but leaves are turning yellow. Three are bad in one garden though a forth nearby looks good. We have had a lot of rain here this summer and the ground is damp now. Pictures attached. Thanks!!!
Montgomery County Maryland
Andromeda (as well as rhododendrons and some other broad-leaved evergreens) may lose some old leaves in the fall naturally. Most of the yellowing leaves look about 3-4 years old--which may have been a year when the plant produced a lot of leaves and, thus, losing them looks like a lot of leaf loss.
Older andromeda do not stay dense and tight with foliage. You'll have to prune to achieve that over the years. If you have older shrubs that have grown spindly, you can rejuvenate them by heavy pruning. The best time to prune these plants is soon after flowering in spring, so not to interfere with flower bud formation for the following year.
Your andromeda also have a bad infestation of lacebugs. These sucking insects are under the leaves and each time they feed they leave a little white dot. All those dots add up to the stippling effect you see. You can use horticultural oil on them--but you must get it under the leaves. Here's what you need to know: https://extension.umd.edu/hgic/topics/lace-bugs-trees-shrubs
Plants love moist soil. As long as the shrubs are not sitting in water or completely soggy soil for long periods, they should be okay. Well-drained soil is good. If you think the soil is staying sodden too long, try grading the soil or putting in very shallow swales to carry off some water.
Thank you, Ellen!!! This is very helpful!!