Drought Stress in Trees

If you've recently planted a new tree, you may be wondering how to care for and protect your investment for years to come. The biggest threat to young or newly planted trees is heat and/or drought as they have small juvenile root systems that cannot reach water reserves deep in the soil. It is common to see symptoms of stress in trees 4 years old and younger, although mature trees can suffer stress in extreme conditions as well. Symptoms vary from species to species and severity of stress, but common indicators include, yellowing or browned leaves, wilted branches and leaves, leaf drop or premature fall color display.

How to prevent heat stress:

Because we can’t simply adjust the thermostat or turn on the rain, the only way to protect your tree from heat or drought stress is adequate watering. Juvenile trees should be watered regularly when sufficient rain is not received. A young tree requires about 2.5 gallons of water per caliper* inch and should be watered slowly to allow moisture to reach deep into the soil.

If you notice drought stress, do not be tempted into overwatering as your tree can easily drown if applied water is increased drastically. Continue watering at a rate of 2.5 gallons per caliper* inch, slowly increasing the frequency of watering. Instead of watering weekly, you should increase to water every 4-5 days when the weather is exceptionally hot. It is important to continue watering regularly until the ground freezes to help your tree establish before the cold of winter.

If your tree appears stressed, wait until spring to count your loses. Newly planted trees often show symptoms of stress through the hot seasons and still come back the following year with minimal permanent damage.

*caliper inch = diameter of tree trunk