Question
I have a fairly large shammel ash tree in my front yard.  The lawn area is about 700 square feet & on the north side of the yard my Santa Ana Bermuda grass does not grow very well.  I live in Peoria, AZ.  I would like to have the tree branches trimmed up higher so that it will allow more sun on the lawn.  This is the first of August and would this be a good time of the year to trim the tree or should I wait.  Would you advise your advice on this tree?

Thank you in advance for your help.

Answer
You need to wait until the fall--when the leaves have started to fall would be ok. pruning it now would attract borers and they could infest the tree. Pruning in late summer can encourage new growth which can be cut short at the first frost and impede next spring's growth. In the fall, prune when frost is imminent and leaves are falling. In spring time, prune before new growth is under way. Never prune a tree in mid-growing season because it will be less effective and may shorten the life of the tree.


Prune the dead branch off about 1/4 inch from the trunk. This will leave a branch collar and the wound will heal over by itself. If the wound is more than 6 inches across after the cut I would paint the area with a wound dressing. This will keep water from getting into the wound. On wound less than 6 inches across I would leave natural and not paint.

On large trees it is best to make the first cut about a foot from the trunk on the under side then cut the branch off from the top leaving a stub about a foot long. Then you can prune off the stub and the heavy limb will not split the bark on the trunk.
Here is a web link to how to prune trees with a drawing of the large limb pruning method.
 http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/text/pruning.ht