Ask Mr. Smarty Plants

"Green Cloud" is the trademarked name of a cultivar of Leucophyllum frutescens (Texas barometer bush), also known as Cenizo and Texas Ranger. Green Cloud was released in 1982 and trademarked by Texas A&M. Instead of the fuzzy silver leaves of Cenizo, Green Cloud has smoother, dark green leaves.  When plants that have been doing well for several years suddenly begin to deteriorate, about all you can do is ask what in the environment has changed to cause this problem? 

We are going to assume that the growth habits of Green Cloud are near enough to the species habits that we can group them together in trying to analyze what is going on. This Texas Native Plants Database from Texas A&M on Cenizo discusses some of the requirements of growing the plant successfully, and especially warns about the susceptibility to cotton root rot (Texas A&M plantanswers). The plant should not be fertilized nor overly watered; humidity and high night temperatures are lethal. You probably already know that Cenizo requires a well-drained soil, which will also discourage cotton root rot. 

Two disease or insect possibilities are scale (University of Illinois Extension) and powdery mildew (University of California Integrated Pest Management). 

Since we are not plant pathologists and it is virtually impossible to diagnose a plant's problems without seeing it, we suggest you first examine your affected plants for any of the possible problems discussed above. Then, contact the Arizona Cooperative Extension Office for Pima County. If others in your area are having the same difficulty, the Extension Office would be in the best position to diagnose and recommend treatment.