The answer, according to experts is, "No."
As Homeowners, we like to trim our trees as Summer begins to wind down and before leaves begin to fall. Who, after-all, wants to be outside on the weekends raking up huge Mulberry or tiny Chinese Elm leaves when we can be enjoying ourselves while watching football or attending family and community events?
Well, according to The National Arbor Day Association at arborday.org, Fall is the worse time to trim trees for this simple reason, "Because decay fungi spread their spores profusely in the fall and healing of wounds seems to be slower [in] fall on cuts, this is a good time to leave your pruning tools in storage."
So, if not in Fall, when? Trees and shrubs, with dead or dying growth can be trimmed throughout the year but Winter is the best time to trim trees for the following reason: "Pruning during dormancy is the most common practice. It results in a vigorous burst of new growth in the spring and should be used if that is the desired effect. It is usually best to wait until the coldest part of winter has passed."
Well, there you have it. Perhaps Fall is a great time to get out outdoors, rake fallen leaves into little mountains, or molehills, and enjoy a little exercise!
For more information please visit the National Arbor Day Foundation's website: arborday.org