KC Gardens

Summer’s drought and heat are taking a toll on trees in Kansas City

Many species of trees have dropped their leaves as a natural defense mechanism to preserve moisture.
Many species of trees have dropped their leaves as a natural defense mechanism to preserve moisture.

When it comes to predicting the Kansas City weather, abnormal is normal. Remember the saying, “if you don’t like the weather, wait a day and it will change.” This year’s growing season has illustrated that.

First it was warm early, then cooler later. Rainfall has been all over the board. And let’s not forget the hordes of insects and random leaf diseases. As a result, plants are stressed.

The Johnson County Extension office has heard your concerns. You want to be assured everything will be fine and you’ll not lose your beloved trees.

Driving around, I see the signs of stressed trees. Leaves are brown or scorched or branches are bare. A multitude of factors are to blame, but drought is the main cause. The U.S. Drought Monitor places much of the metro area in the severe or extreme drought conditions. This dry period started almost a year ago and is continuing.

Drought conditions have caused many tree species to shed leaves. While it’s alarming to see this fall-like behavior, it is a normal defense mechanism. The tree’s natural instincts have kicked in to conserve moisture. But if the drought continues, the stress will build and result in the decline or death of many trees.

Watering will stave off the effects of the drought but may not always be practical. Prioritizing is the best strategy. Water the most valuable trees; younger trees and evergreens suffer the most. Large, mature native trees will just need to fend for themselves.

Red maple stress
This summer’s intense sun has scorched many leaves. Dennis Patton

Adding to the drought conditions has been the hotter summer. The intense sun has caused leaves to scorch brown along the edges. This has left trees stressed, and many of these leaves have dropped.

There is not much we can do to prevent scorch. Timely watering can help, but many times leaves just cannot cope. Species susceptible to scorch or those with other issues such as trunk damage that limits water movement will suffer.

Trees that are outside their ideal environment are also vulnerable. For example, Japanese maples need protection from the hot sun so should not be planted in a location that gets intense afternoon sun.

Japanese beetles have taken their toll by feeding on many plants. Linden trees, for example, are completely brown. This pest has raised concern for the health of the trees. Honestly, the damage from the beetle is the least of our worries; it looks worse than it is. By the middle of summer, trees have manufactured much of their stored energy for next season.

The defoliation, while still of concern, is not as life-threatening as the drought.

What’s next? Stay tuned, as we cannot predict long-term weather patterns with great accuracy. But if you are worried, now might be a good time to water.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? Email them to garden.help@jocogov.org.