Colorado Tree Pruning Calendar by Month & Species

Prune With the Colorado Calendar, Not Against It

When you prune matters as much as how you prune. Colorado’s short growing season, dry air, and hard freezes mean a cut made in the wrong month can set a tree back for years — or open the door to disease. Here is the month-by-month guide our crew actually works from.

The Front Range Pruning Calendar

Months	What to prune	Notes
November – February	Oaks and elms; heavy structural work on deciduous trees	Oak wilt and elm bark beetle vectors are dormant — the only safe window for these species
February – March	Structural pruning, crown thinning, most deciduous trees	Dormant cuts heal fastest; spring growth fills in quickly
April – May	Minimal work; only deadwood and safety cuts	Birds are nesting; sap flow is heavy; avoid oaks and elms entirely
June – August	Deadwooding, hazard limbs, storm-damage cleanup	Good time to remove deadwood on cottonwood and ash; light touch only
September – October	Light corrective pruning; prepare for winter	Reduce ice-loading risk on vulnerable species; no major cuts

Species Notes

• Cottonwoods — deadwood in summer; major structural work in late winter before leaves break.
• Ash (EAB monitoring) — prune in winter; summer cuts attract the same beetles that spread disease.
• Spruce and pine — prune deadwood year-round; never remove more than a third of live canopy.
• Fruit trees — dormant late-winter pruning for structure and fruit production.
• Maples, honeylocust, birch — late-winter pruning avoids heavy sap flow and stress.

The Rule We Never Break

We never top trees. Topping removes the canopy that feeds the tree, leaves huge wounds that rot, and triggers weak regrowth that breaks in the next storm. Proper crown reduction keeps height in check without destroying structure — and it is always done on the right species at the right time of year.