University of Illinois Extension

Deep Watering Evergreens

Be proactive and deep water your evergreens this fall, recommends Martha Smith, a University of Illinois Extension horticulture educator.

“Water as much of the root zone as possible,” said Smith. “Don’t water at the base of the trunk but water out near the drip line—the outside perimeter of foliage. More water-absorbing roots are in this area.

“Place a hose on a slow trickle and let the water soak in. Move the hose around the plant to ensure you are reaching as much of the root zone as possible.”

This is necessary because a major concern for evergreens is winter survival if the plants have little soil moisture. Pine, spruce, fir, yew, juniper, and arborvitae are easily stressed from summer’s extreme temperatures and are in real danger if they can’t pull moisture from the soil to replace what is normally lost due to winter weather, she noted.

“As a result, evergreens can dry up, turn brown, and die in the spring,” she said.
During the winter dormant season top growth ceases in evergreens. However, roots are still active until soil temperatures drop below
35 degrees F.

“Evergreen foliage is exposed to the elements all year round,” Smith said. “Winter winds pull out available moisture and the roots need to take up moisture to replace this loss.”

A dry growing season followed by a cold windy winter with little snow can trigger damage in evergreens.  The wind blows over the evergreen foliage and sucks out any available moisture.

“In February and March, we often have warm, spring-like days,” she said. “It is at these times that the evergreens try to replace what moisture they have lost.  If the soil is dry, the plants suffer.

“In comparison, deciduous material such as maples and oaks lose very little moisture in the winter. When their leaves emerge, it usually means we are experiencing ample spring rain to allow for adequate water uptake.”

Smith also recommended that homeowners avoid using any de-icer materials along walkways or roads near evergreens. Salt-laden runoff can restrict water uptake.