Summer Tree Care Tips For Homes & Businesses in Colorado

Trees are one of the most valuable additions to any landscape in Northern Colorado. Whether shading a backyard patio in Fort Collins or enhancing curb appeal outside your business, healthy trees bring beauty, value, and welcome relief from our intense summer sun. But Colorado's hot, dry summers and unique elevation can stress even the hardiest trees, especially if they're young, newly planted, or already facing environmental challenges.

The good news? A few proactive steps can help your trees not just survive, but truly thrive throughout the season. Here are our top summer tree care tips, specifically tailored to Northern Colorado's semi-arid climate and the unique needs of gardeners in hardiness zones 4b through 6a.

Water Deeply and Infrequently

Trees in Colorado benefit from deep, infrequent watering rather than shallow, frequent sprinkling. Deep watering encourages deep root growth and helps trees become more drought-resistant.

A mature tree needs approximately 10 gallons of water per inch of trunk diameter once per week. For example, a tree with a 10-inch diameter trunk needs about 100 gallons per watering session—that might sound like a lot, but it's what your tree needs to stay healthy in our dry climate.

Water early in the morning when temperatures are cooler and evaporation is minimal. Focus on the tree's drip line (the area directly below the outer edge of the branches) rather than watering near the trunk. You can use a soaker hose, slow-release watering bag, or simply let a hose trickle slowly for 30–60 minutes to achieve that deep saturation.

Apply Mulch—But Keep It Away from the Trunk

Mulch is your tree's best friend during Colorado summers. It keeps roots cool, conserves precious moisture, and helps regulate soil temperature—all crucial benefits in our challenging climate.

Apply 3–4 inches of organic mulch around the base of your tree, creating a ring that extends to the drip line. The important part is to keep the mulch 2–3 inches away from the trunk to prevent rot and pest issues. Think of it as creating a donut shape around your tree.

Avoid "volcano mulching"—that's when mulch is piled directly against the trunk like a volcano. While it might look tidy, it can suffocate roots and create the perfect environment for harmful insects and diseases.

Inspect for Pests and Diseases

Summer is peak season for insect pests and fungal diseases that can weaken trees. The combination of heat, stress, and an active growing season makes trees more vulnerable to various issues.

Watch for warning signs like wilting leaves, sap oozing from bark, unusual holes in foliage, or early leaf drop. Common culprits in Northern Colorado include aphids, borers, cankerworms, and fire blight; early intervention will be the best defense against these issues.

Catching issues early allows you to treat them before they spread or cause serious damage. Neem oil, insecticidal soaps, and horticultural oils are excellent organic solutions for many common pests. If you're unsure what you're dealing with, use our Pest Finder or Disease Finder for more information.

Go Easy on Summer Pruning

While light pruning to remove dead, damaged, or diseased branches is perfectly fine in summer, avoid heavy pruning during the hottest months. Removing too much foliage can stress the tree and make it more vulnerable to sunscald and pest problems.

Those leaves work hard to shade the trunk and branches from our intense Colorado sun. Save major structural pruning for late winter or early spring when the tree is dormant and can better handle the stress.

Protect Trees from Mechanical Damage

Summer is the season of active yard work, but be careful around your trees. Lawnmowers, string trimmers, and weed whackers can easily damage bark, especially on young trees. Even minor wounds can become entry points for diseases and pests.

Create mulch rings around the base of your trees to establish a protective buffer zone. Adding mulch eliminates the need to mow or edge close to the trunk and gives your trees a clean, professional appearance.

Avoid Over-Fertilizing in Summer Heat

While a slow-release fertilizer can benefit trees early in the growing season, too much nitrogen during summer can harm your trees. Excess nitrogen stimulates new growth that's tender and vulnerable to heat stress, pests, and drought.

If your trees are well-established and healthy, skip the fertilizer until fall or next spring. If you must fertilize, choose a low-nitrogen, slow-release formula and always follow application rates carefully. When in doubt, complete a soil test to determine your trees' needs.

Provide Shade for Young Trees

Young and newly planted trees are especially vulnerable to Colorado's intense summer sun. If you notice signs of leaf scorch (brown, crispy edges) or sunburn on the bark, consider providing temporary shade using shade cloth or strategically placed shrubs.

Sun protection is vital for thin-barked trees like maples, cherry trees, and certain fruit trees. Even trees that are typically sun-loving can benefit from some protection during their first few summers in Colorado.

Be Mindful of Construction and Soil Compaction

If you're doing summer landscaping or hardscaping projects, be extra careful not to disturb the root zones of nearby trees. Our clay-heavy soils in Northern Colorado are already challenging for trees, and compacted soil from foot traffic or heavy machinery can severely limit root growth and water absorption.

Try to keep foot and equipment traffic away from the tree's drip line whenever possible. If you must work in the area, use plywood or mulch paths to distribute weight and reduce compaction.

Summer Tree Care with Bath Garden Center

Our staff at Bath Garden Center in Fort Collins understands trees, and we know how to help them flourish in Northern Colorado's challenging climate. Our team has years of experience assisting local gardeners in choosing the right trees for our hardiness zones and maintaining them through our unique seasonal challenges.

Stop by Bath Garden Center to browse our tree selection, stock up on summer care supplies, or ask our team any questions about your specific trees. We're passionate about helping you create a landscape that thrives year after year.