Young trees are finicky about watering needs. Take steps to find ideal balance

It is said the best time to plant a tree was 10 years ago. The next best time is tomorrow.

Due to the spread of Emerald ash borer and other diseases, many of us are planting new trees. Summer heat and dry weather make it challenging to keep young trees thriving and not succumbing to the stress. Once planted, watering is the key to summer survival.

Proper water is vital for successful establishment of the roots. It is the difference between success and failure during this first year.

The goal is to keep the tree evenly moist to avoid stress. Knowing when and how much water to apply can be difficult. There are a few tips to follow.

Water young trees deeply, thoroughly soaking the root ball and surrounding soil. Under typical summer patterns, that should happen about once a week.

Watering too frequently can lead to saturated soils as the water does not have time to drain away. Surprisingly, overwatering kills as many trees as underwatering.

How much water should be applied? A useful guide is to apply at least 10 gallons of water to the root ball and a few feet surrounding it as this is the area new roots will develop.

Ten gallons applied slowly enough allows the water to soak into the soil and not runoff. This amount would be a good start for 1 to 2-inch trunk diameter trees. Larger trees will need twice as much.

Creating a low berm a couple feet out and around the planting hole creates a reservoir, holding the water and allowing it to soak in.

Other methods are used to aid in watering. A 5-gallon bucket can be used to slowly soak the roots. Drill one or two small holes, 1/8 inched, in the side near the bottom of the bucket.

This simple strategy is a useful measure to know how much water is being applied. Be sure to move the bucket around the root area to keep all sections of the tree hydrated.

Hang large plastic water bags on the trunk or lay flat on the ground. When filled with water, it slowly soaks the soil.

The method of applying water with a bucket or a water bag are only recommended for the first year of establishment as they do not soak the surrounding soil enough, resulting in a limited tree root system.

Lawn sprinkler systems are not always effective at watering young trees. They can deliver too much water, frequently causing the tree to be overwatered.

A signal of too much water on a tree includes the wilting and yellowing of the leaves. This symptom is similar to not having enough water, which leads people to add more water, potentially killing the tree.

Lawn sprinklers may supply enough water to keep the surrounding grass green but not provide enough water to reach the tree roots. Then the tree succumbs to drought.

Help your new tree establish by removing the grass around the tree and applying a layer of mulch. When combined with timely watering, this will help ensure a beautiful tree for the future. One last tip: Even trees planted two to five years ago will thrive with a drink during more extreme periods of drought.

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

This story was originally published July 27, 2020 at 7:38 PM.