Tree & Shrub Care March 11, 2026

When and How to Trim Trees and Shrubs in the Denver Area

Timing and simple rules that keep your plants healthy and your yard looking good

Trimming trees and shrubs at the right time does more than tidy up the yard. It keeps plants strong, reduces disease and pest problems, and can prevent damage to your home or walkways. In the Denver metro, our dry climate and late freezes mean timing matters. Here is a clear guide to when to trim, what to avoid, and when to call in a pro.

When to Trim Trees in the Front Range

The best window for trimming most trees in the Denver area is late winter or early spring, when the tree is still dormant but the worst of the cold is past. That usually means late February through April, depending on the year. Trimming when the tree is dormant means less sap loss, fewer pests attracted to fresh cuts, and a full growing season ahead for the tree to close wounds and put energy into new growth. In Denver, Arvada, and Golden, many homeowners schedule tree trimming in March or early April so the job is done before leaves are fully out and the calendar gets busy.

Some trees, like maples and birches, can bleed sap if trimmed too late in spring. Trimming them in late winter or very early spring reduces that. For trees that are clearly diseased or damaged, or that have limbs threatening the house or power lines, do not wait for the ideal window. Safety comes first; a pro can remove hazard branches and then plan follow up trimming for the right season.

When to Avoid Trimming Trees

Right after leaves appear. Trees are putting a lot of energy into new growth; heavy trimming then can stress them.
In the heat of summer. Trimming in hot, dry weather can leave cuts exposed when the tree is already stressed by drought.
In fall before dormancy. New cuts can encourage late growth that does not harden off before frost.

When to Trim Shrubs in the Denver Area

Shrubs fall into two rough groups: those that bloom on new growth and those that bloom on last year’s growth. For shrubs that flower on new growth (growth that appears this season), trimming in late winter or early spring is ideal. You shape the plant before it leafs out and it still has the whole season to grow and bloom. For shrubs that bloom on old wood (last year’s branches), trim right after they finish flowering. If you trim those in spring before bloom, you cut off the buds and lose the flowers. A quick check online or with a local nursery can tell you which type you have.

In practice, many people in Lakewood and Littleton do a light shrub trimming in early spring to remove dead or broken branches and keep shape, then do a fuller trim after bloom if needed. That keeps shrubs healthy without sacrificing flowers.

How Much to Remove When Trimming

A good rule is to avoid removing more than about one fourth of the plant in a single year. Taking too much at once can shock the plant and leave it weak or misshapen. Focus on dead or damaged wood first, then branches that cross or rub, then shape. Making clean cuts just outside the branch collar (the slightly swollen ring where the branch meets the trunk or another branch) helps the plant close the wound. Ragged or flush cuts can slow healing and invite disease.

Why Trimming Helps in Colorado

Our climate is tough on plants. Dry air, strong sun, and late frosts can stress trees and shrubs. Well timed trimming removes weak or diseased wood so the plant can put energy into strong growth. Opening up the canopy lets light and air in, which can reduce disease and improve flowering. Keeping branches off the roof and walkways prevents damage and keeps your property safer. In Centennial, Parker, and across the Front Range, a once or twice yearly trim is often enough to keep things in good shape.

What You Can Do Yourself vs When to Call a Pro

Small shrubs and low branches are manageable for many homeowners with hand pruners or loppers. Keep tools sharp and clean to avoid tearing stems or spreading disease. For anything above shoulder height, large branches, or work near power lines, hiring a pro is safer and often leads to better results. Professional tree trimming and shrub trimming services know how to make the right cuts, dispose of debris, and avoid damaging the tree or your property. If you have a tree and shrub care program, trimming is often included on a schedule that fits the Denver season.

Feeding and Care After Trimming

After a trim, plants benefit from consistent water and, when appropriate, feeding. Do not overwater; soggy soil can cause root problems. A tree and shrub fertilization program can give plants the nutrients they need to recover and put on strong new growth. If you notice pests or odd spots on leaves after trimming, disease control or insect control may be needed. Catching those early keeps plants healthy and saves money over time.

Quick Reference: Trimming Calendar for Denver

Late winter to early spring (February to April): Most trees; shrubs that bloom on new growth; general cleanup of dead wood.
After spring bloom: Shrubs that flower on old wood (trim right after flowers fade).
As needed: Broken or hazardous branches; limbs touching the house or blocking paths.

Getting on a schedule that matches your plants and our climate takes the guesswork out of when to trim. If you want help with tree trimming, shrub trimming, or a full tree and shrub care program, contact us for a free quote. We serve the full Denver metro, from Boulder to Castle Rock and everywhere in between.