Determining a time to trim your tree's can often be a frustrating quest. I have heard many different opinions from the Tucson Tree Service community. Depending on your variety of tree you may have a need to trim at a certain time which is different than others.
So When should I Prune my Tree's in Tucson? A simple answer is Late February. The idea is that trimming right before spring allows the tree to heal and generate new shoots quickly causing less stress and harm from micro organism's. I have also studied that citrus tree's should have cleaning and limb removal done in fall, with a lighter tip pruning in spring to stimulate new growth. I think the knock with fall tree trimming is that a tree is going dormant and preparing for winter, this is believed to cause a slower heal time in the cut.. etc. I feel that early fall is an acceptable time for renovation in Tucson and summer sometimes too due to preparing for Monsoon Storms.
Often we do a lot of trimming in the fall to clear mountain views. The customer often gets 6 months of un obstructed vies before the new spring growth comes. Having watched these jobs and returned year after year I have noticed no ill effects on the fall trimmed vegetation. Also I have never experience new shoots that grow then get frozen from fall pruning, but Mind you that we have a lot branch standard tree's that are close in relation to shrubs and our winters often do not include heavy freezes that they see up north. If you have a central leader tree or semi branch standard tree that is large or non native I recommend waiting till late winter/early spring.
Each situation and tree is different, so consider all options, for example the coral tree is to be trimmed in April and ornamentals in fall after flowering. Recently we returned to see a tree that had been frozen in Feb 2011. At that time our recommendation was to wait till this fall to clean and lightly trim. Over the last yr and a half they have had many landscapers tell them they needed to trim there tree, how happy the are to have waited. We did the cleaning and the tree is now healthy with a crown full again. Micro organisms spread but were not helped by more cutting opening new sores to attack.
So use good judgement in deciding when you should Prune our Tree's in Tucson? And as always we are here to help.