When is the best time to trim the tree ? What is the best spray to use on the fungus at the tree trunk ? When is the best time to cut back my hibiscus ? When is the best time to trim an Arizona ash tree ?
The cottonwood and Arizona ash are best pruned just prior to the new growth commencing in the early spring. Some time around mid-February will be fine. I have no idea what kind of fungus you may have, but doubt that it needs spraying at all. You can cut your hibiscus back at any time. It may stimulate new growth but this does not matter because you must bring it into a protected location any time the temperature is predicted to go below 34 degrees F.