Q: What makes the leaves on my red barberry turn yellow? We have a chlorosis problem in Boise, ID, so have been treating for that.
Leaves on shrubs turn yellow for several reasons. Too much or too little water will do it. Spider mites also cause yellowing of leaves. Look at the undersides of the leaves for webs and tiny bugs. A strong stream of water will wash them away. Repeat every 3 to 4 days for a week or two. Best And Happy Yardening, Nancy