The southward side of my Viburnum is getting yellow leaves. The rest of the plant looks nice and dark green. I originally thought this was the color of new growth but the leaves are starting to dry out from the tip of the leaf. Please see photo. Any ideas what it is and what I should do?
The leaves look chlorotic. This is often a sign of insufficient iron, although that does not mean your soil is lacking iron. It means the plant, for several possible reasons, cannot take up the iron sufficiently. But chlorosis has many other possible causes, some nutrient related, some disease related, some weather related.
For starters, you should get a soil test done:
This will tell you your soil pH. High pH soils can be too alkaline for the plant to take up iron properly. Starting from the test, you can decide on a strategy, which might be to do nothing, or apply an iron foliar spray, or try to adjust the soil pH. Read here: