If you’ve noticed leaves turning brown at the edges or dropping earlier than usual this August, you’re not imagining it, and you’re not alone. Colorado’s combination of high heat, low humidity, and unpredictable rainfall is hard on trees every summer, even ones that have been established in your yard for years. The tricky part is that trees rarely show stress right away, so by the time you notice a problem, the tree has often been struggling for weeks. The good news is that a few changes to how you water can make a real difference.
This guide covers why Front Range summers are so tough on trees, how to tell the difference between normal seasonal changes and real drought stress, and a simple watering routine you can actually stick with. We’ll also get into why the sprinkler system watering your lawn usually isn’t doing much for your mature trees. By the end, you’ll know what to look for and what to do about it.
Why Colorado Summers Are So Hard on Trees
Colorado’s climate puts trees in a tough spot every year. Hot days, low humidity, and long stretches without meaningful rain all pull moisture out of leaves faster than most tree species evolved to handle. Add in Denver’s periodic watering restrictions, and it’s easy to see why so many yards start showing stressed trees by mid to late summer. None of this means your tree is doomed, but it does mean most trees need a bit of extra help getting through the season.
Low Humidity and Uneven Rainfall Along the Front Range
Because the Front Range sits at elevation with low humidity, moisture evaporates from soil and leaves faster than it would in a wetter climate. Rain, when it does come, is often brief and heavy rather than the slow, soaking rain that actually reaches tree roots. That combination means a green lawn after a quick summer storm can be misleading. Your trees may still be thirsty even when the grass looks perfectly fine.
Which Trees Are Most at Risk
Newly planted trees are usually the most vulnerable, since their root systems haven’t had time to spread out and reach deeper, more reliable moisture. Shallow rooted species and trees planted on the south or west side of a property, where afternoon sun and reflected heat are strongest, also tend to struggle more than others. Even a well established shade tree can start showing stress after several years of hot, dry summers in a row, so age alone isn’t a guarantee of resilience.
How Do I Know If My Tree Is Suffering from Drought Stress?
Watch for leaves that wilt or curl in the afternoon heat, brown and crispy edges on the leaves, and leaves dropping earlier than they normally would for the season. Some trees also show thinning canopies or an unusually heavy crop of seeds or fruit, which is a stress response rather than a good sign. If you notice any of these, it’s worth checking soil moisture before assuming the worst. Mature trees can often bounce back once watering is corrected, but the sooner it’s addressed, the better the outlook tends to be.
Why Sprinklers Alone Don’t Cut It for Mature Trees
Standard lawn sprinklers are built to wet the top few inches of soil, which is exactly what grass needs and exactly what a mature tree doesn’t. Most of a tree’s water absorbing roots sit in the top twelve inches of soil, but they spread out two to three times wider than the tree’s canopy, far beyond where a sprinkler typically reaches. That mismatch is why a lawn can look perfectly green while the tree next to it is quietly drying out.
Deep Root Watering vs. Surface Irrigation
Deep root watering means soaking the soil slowly enough that moisture actually reaches those deeper, wider roots instead of running off or evaporating from the surface. A soaker hose, or a slow trickle from a regular hose moved every so often around the tree’s dripline, works far better than a quick blast from a sprinkler head. The goal is steady, deep moisture, not a quick rinse across the surface. This matters most for the large, established trees that took decades to grow and would take just as long to replace. Watering early in the morning or later in the evening also helps, since less moisture is lost to evaporation compared to watering under the midday sun.
A Simple Watering Routine Homeowners Can Follow
You don’t need a complicated schedule to keep your trees healthy through a Colorado summer, just a bit of consistency. Bear Creek’s plant health care team recommends starting with the soil itself rather than watering on a fixed schedule regardless of conditions. A little observation up front saves a lot of guesswork later.
How to Check Soil Moisture Before You Water
Dig down about four inches, roughly twenty inches out from the trunk, and feel the soil. If it’s dry at that depth, it’s time to water; if it’s still moist, you can comfortably wait a bit longer. According to Denver Water’s tree care guidance, checking regularly during dry stretches works better than watering on autopilot, since a tree’s needs shift along with the weather.
The Role of Mulch in Retaining Moisture
A two to four inch layer of organic mulch spread within the tree’s dripline helps the soil hold moisture longer between waterings and keeps competing grass roots away from the tree. Keep mulch pulled back an inch or two from the trunk itself so it doesn’t trap moisture against the bark. It’s a small step that meaningfully reduces how often you’ll need to water over the course of the summer. Mulch also moderates soil temperature, which keeps roots a bit cooler and more comfortable during the hottest stretches of July and August.
How Often Should I Water Mature Trees in the Summer?
During a hot, dry stretch, most mature trees benefit from a deep watering session roughly once a week, adjusted based on rainfall and how quickly the soil dries out. Newly planted trees typically need water more often since their root systems haven’t spread out yet. There’s no single number that fits every yard, which is why checking the soil directly is more reliable than following a fixed calendar. When in doubt, water deeply and less frequently rather than lightly and often.
When Drought Stress Needs a Professional’s Eye
If you’ve adjusted your watering and a tree still isn’t bouncing back, or if you’re seeing dieback in the canopy or bark that’s starting to crack, it’s worth having a certified arborist take a look. An arborist can tell you whether the issue is really about water, or whether pests or disease have moved in while the tree was weakened. Catching that early usually means a far simpler fix, and a much better chance of saving the tree altogether. A professional assessment is also useful if you’re simply unsure whether what you’re seeing is normal seasonal change or an actual warning sign, since that distinction isn’t always obvious to the untrained eye.
Helping Your Trees Thrive Through the Rest of Summer
A little consistency goes a long way toward getting your trees through a Colorado summer in good shape. Check the soil before you water, water deeply and slowly rather than quickly and often, and keep an eye out for the early signs of drought stress so you can catch problems while they’re still easy to fix. Mature trees are one of the most valuable things in your yard, and they’re also the slowest to replace, so a bit of attention now is worth it. Small habits, like checking the soil before you water and keeping mulch topped off, add up to a noticeably healthier landscape by the time fall arrives. If your trees are showing signs of stress despite your best efforts, reach out to Bear Creek Tree Service and we’ll take a look, figure out what’s really going on, and help you get your landscape back on track.