Winter Tree Care: Pruning Tips to Protect During Dormancy

Winter tree care includes understanding pruning dos and don’ts. Knowing what, when, and how to prune native Arizona trees can keep them growing healthy and strong during winter dormancy and beyond.

What Happens While Trees Are Dormant?

Understanding dormancy helps us understand the role and timing of tree pruning in their life cycle. According to Penn State Extension, “Dormancy in trees is the time at which the tree is alive but not actively growing. It is during this time that the inner workings of a tree slow down and pause until conditions change to allow for productive growth. Unlike evergreen tree species, which can retain their foliage on account of adaptations, deciduous trees enter into dormancy to prevent the loss of water and nutrients and to avoid the damage cold temperatures produce.”

The Arbor Day Foundation recommends trimming trees during their dormant season because it’s more efficient and effective when you can see and access entire limbs more easily. Bare limbs and branches are also easier to handle and remove than those weighed down with foliage.

Tree pruning and trimming are great for their long-term health and growth. Proper pruning improves air circulation and sunlight penetration, which can prevent tree disease and make it easier for trees to absorb vital water and nutrients (from the sun and the soil). 

Which trees to Trim This Winter

Live in Arizona? Trim your deciduous trees (such as redbuds and fruit trees) and evergreens over winter while they’re dormant. Here are some specifics by tree species.

• Deciduous Trees: Trim local deciduous trees from December through February while their branches are bare. This makes it easier to see the structure of trees like redbuds and Japanese Maples, and to check for signs of tree disease.  
• Evergreens: Evergreens don’t lose their leaves, but trimming them during the same winter period (Dec-Feb) when growth slows down will keep them from overgrowing.
• Mesquite Trees: Prune mesquite trees from late winter to early spring to lower the risk of pest activity or infestation. 
• Citrus Trees: Lightly shape around mid-February to avoid damage from any potential frost if you live in one of our colder/higher-elevation areas. Don’t overtrim or overprune these delicate trees. 

Tree Trimming Tips for Safety and Success

Here are some tried and true tree trimming tips:

1. Safety first. Wear your protective gear, including insulated gloves, boots, and safety glasses.
2. Use equipment that works properly and is adequately sharpened.
3. Cut just outside the branch collar to encourage proper healing.
4. Don’t make your cuts flush with the trunk, or leave stubs on the tree. 
5. Remove any branches that cross, rub against each other, or grow inward.
6. Sterilize your trimming and pruning equipment after trimming each tree to avoid spreading pests or disease to the next tree you prune. 
7. Know the most prevalent Arizona tree diseases (and pest activity) to deal with threats proactively. If you’re unsure whether a tree in your yard is diseased, don’t trim it. Ask an Arizona tree care expert. breakage.