Time for Planting
Trees and shrubs should be planted in the fall after they have become dormant (about early November) or in the spring before new growth appears (around late March). Balled and burlapped trees and shrubs may be planted any time of the year provided they were dug during the dormant period and after planting receive ample water during hot, dry weather. It is advisable to spray the foliage of broadleaf evergreens with transpiration inhibitors such as "Wiltpruf"* to minimize transpiration. Broadleaf evergreens planted in the fall should also be so treated to protect the foliage from sun and severe winter winds.
--West Virginia University
Trimming of your Trees
Given Santa Barbara's climate, trimming of your trees can be done year round. We also recommend tree maintenance during the fall season for two simple reasons:
a) to reduce the amount of Autumn's lose leafs on your lawn.
b) to reduce the potential risk of fires or broken limbs during windy days.