Don’t Let Your Des Moines Trees Succumb to Drought Stress This Summer

Just when Des Moines residents thought they could breathe easy, drought is knocking on our door again. Iowa ended a devastating four-year drought in May 2024 – one of the longest streaks the state has seen since the 1950s – but that relief seems to be short-lived.

After just one year of recovery, Iowa’s long-range forecast shows troubling signs that the state could see an elevated warm and dry period over the next few months, worsening already abnormally dry conditions across Polk County. Your trees, which may have just started recovering from years of stress, could soon face another battle for survival. The difference is, this time you know what’s coming and how to save your trees.

Key Takeaways

• Des Moines is facing another potential drought after just one year of recovery from a devastating four-year dry spell, putting already weakened trees at serious risk.
• Drought stress triggers a domino effect in trees – root damage leads to leaf problems, which stops food production and makes trees defenseless against pests and diseases
• Drought stress symptoms range from early signs of leaf wilting and yellowing to critical signs like bark cracking and significant branch dieback.
• Proper watering requires deep, infrequent application at the drip line using soaker hoses, aiming for 1 inch per week applied slowly to penetrate Des Moines’ clay soil.

What Drought Stress Actually Does to Your Trees

To understand why drought is so devastating, you need to know that water isn’t something trees “drink” – it’s the foundation of nearly everything they do.

Water is where all the chemical reactions inside tree cells happen. It’s the main component of living cell material, and trees use it as a raw material for photosynthesis (the process that creates their food). Water also creates the pressure that helps new cells expand and grow, which is how trees get bigger and stronger.

When drought hits, here’s what happens inside your tree:

The Roots Suffer

The delicate hair-like roots that extend from the main roots are responsible for most water uptake, and they’re confined to the upper 15 inches of soil – exactly where drought hits first. When soil dries out, it shrinks away from these tiny root hairs, creating gaps. As your tree continues losing water through its leaves, water gets pulled out of root cells, causing them to shrink and eventually die.

The Leaves Shut Down

Your tree’s first defense is closing the tiny pores (stomates) in its leaves to stop water loss. The problem is that these same pores are how trees take in carbon dioxide for photosynthesis. When they close, your tree can’t make food. Recovery from this shutdown is slow. Even when water becomes available again, it may take hours, days, or even weeks for normal function to return.

Food Production Crashes

Without carbon dioxide, photosynthesis grinds to a halt. This forces the tree to start shedding leaves to conserve the little energy it has left. But fewer leaves means even less ability to make food when conditions improve, creating a downward spiral that’s hard to reverse.

Defenses Crumble

Trees use the carbohydrates from photosynthesis to make defensive compounds that fight off insects and diseases. As food production drops, so does the tree’s ability to defend itself. That’s why drought-stressed trees become sitting ducks for pests like borers and scale insects and diseases.

What Does a Drought-Stressed Tree Look Like?

Drought stress symptoms can range from subtle changes you might barely notice to obvious signs that your tree is in serious trouble. Knowing what to look for – and how urgent each symptom is – can mean the difference between saving your tree and losing it.

Here’s what to watch for:

• Wilting or drooping leaves during the hottest parts of the day
• Lighter green to yellow-green foliage throughout the canopy
• Leaf scorch (browning) around the edges
• Leaf curling
• Premature leaf drop
• Smaller than normal leaves
• Unusually heavy seed or fruit production
• Branch dieback starting from the top of the canopy
• Bark cracking and peeling
• Surface roots becoming visible through soil cracks
• Significant thinning of the canopy

How to Save Drought-Stressed Trees

When your trees are showing drought stress, how you water can make the difference between recovery and decline. Unfortunately, most well-meaning homeowners use techniques that waste water and don’t actually help their trees. Learning the right approach can save your trees – and your water bill.

The Right Technique

Deep, infrequent watering is key. You want to penetrate deeply into the soil to encourage deep root growth, not just a wet surface. Focus on the drip line – the area directly under the outer edge of your tree’s canopy – not the trunk. This is where the feeder roots that absorb moisture are located.

Water early in the morning to minimize evaporation loss. Our Des Moines clay soil presents a challenge because water can run off the surface instead of penetrating. Use soaker hoses or drip irrigation to apply water slowly, allowing it to soak in rather than pool or run off.

How Much Water Your Trees Actually Need

Large mature trees require substantial amounts of water – often hundreds of gallons per week during drought conditions. For practical purposes, aim for about 1 inch of water per week during drought, applied slowly over several hours.

H3: Signs You’re Watering Your Trees Properly

You’ll know you’re watering correctly when the soil is moist 12-18 inches deep at the drip line. If water is pooling or running off the clay soil surface, you’re applying it too fast. Watch for overwatering signs too, like yellowing leaves starting from the bottom of the tree, mushy or black roots, fungal growth around the base, and a sour smell from the soil.

Frequently Asked Questions About Caring for Drought-Stressed Trees

How can I tell if my tree is dying from drought or something else?

Drought stress typically affects the entire tree gradually, starting with leaf symptoms and progressing to branch dieback from the top down. Disease or pest problems often show more localized symptoms or unusual patterns. When in doubt, have a Certified Arborist evaluate your tree.

Should I fertilize my drought-stressed trees?

No, you should not fertilize your drought-stressed trees. Fertilizer can actually further stress trees affected by drought by encouraging new growth they can’t support. Focus on water and mulch first. Once your tree recovers, then consider fertilization.

Can I prune drought-stressed trees to help them recover?

Light pruning to remove dead branches is okay, but you should avoid major pruning on stressed trees. Pruning stimulates new growth that requires water and energy your tree doesn’t have. Wait until recovery begins.

When is a drought-stressed tree beyond saving?

Trees with extensive branch dieback (more than 50% of the canopy), severely cracked bark on the main trunk, or signs of advanced decay are often beyond recovery. Safety also becomes a concern when drought stress has compromised tree structure.

Get Professional Help for Your Drought-Stressed Trees from Arbor Masters

Recognizing drought stress early and watering correctly can save most trees, but some situations require professional expertise. Whether your trees need immediate assessment or you want to build their long-term resilience, you don’t have to navigate this alone.

Arbor Masters’ ISA Certified Arborists can assess your trees and create a recovery plan. While proper watering is your first line of defense, we can work together with treatments like deep root fertilization this fall and strategic pruning this winter to help your trees bounce back stronger. We’ve guided countless Des Moines homeowners through drought recovery, and we know exactly what your trees need to survive.

Call 515-218-2025 today to schedule a free estimate. Your trees can’t wait – and neither should you.