Trimming or Pruning in the Winter?
The effects of cooler temperatures vary with plant and tree species stage of growth, age, general health, and of course water content. Young, actively growing, flowering, and/or dehydrated plants and trees tend to be most vulnerable to the colder temperatures. In most cases, you should not prune in the winter, because anything that grows after pruning will most likely freeze and die. You could lose even more of the plant or tree because of this.
Luckily, Arizona is one of the few states that the climate allows for the trimming or pruning of certain species in the winter months. Non-Deciduous Trees, Conifers such as Pine and Cypress, as well as Summer Blooming Shrub can all be pruned and trimmed in the winter. Many summer flowering shrubs bloom on the current year’s growth. Pruning them back in later winter encourages them to produce lots of new growth that following summer and will result in more flowers… Don’t be afraid to cut fast-growing plants. You will still have time for the Blooms.