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Neighbors of DuPage

Tree care tips—Watering trees and shrubs

Aug 01, 2017 08:30AM ● By Ben Scott

As summer is coming to an end, it is essential that trees and shrubs receive the proper amount of water in order to survive. Excessively dry soils cause the death of small roots, and reduce the tree’s capacity to absorb water, even after the soil is remoistened, causing unnecessary stress and potentially death. Keep your trees and shrubs adequately watered by following a few simple guidelines.

Check the soil moisture. Soil moisture is the best indicator for whether living conditions are too dry or too wet, and should always be checked before watering. A metal rod may be the most convenient tool for a homeowner to obtain and use for the purpose of testing soil moisture. Very dry soil will resist penetration of the rod and indicate the need for watering. Soil moisture meters are cheap and easy to use as well and can be purchased at your local hardware store.

Newly planted trees. Proper watering is the single most important factor in the care of transplanted trees. 90% of newly planted tree mortality is due to either too much or too little water. Newly planted trees need approximately two inches of water per week during normal conditions, and more in drought conditions. These trees and shrubs may need to be watered for 2–3 years until their root systems become established enough to gather enough water independently. Large trees that are transplanted may take longer. For the first few months of the growing season after a tree is planted, the tree draws most of its moisture from the root ball. The root ball can dry out in only a day or two, even though surrounding soil remains moist. Water both the root ball and the surrounding area by letting the hose leak water slowly at the base of the tree. Keeping the base of the tree free from other plants by weeding reduces competition for nutrients and water, and watering in the early morning and evening optimizes the water used by minimizing evaporation.

Established trees. The top 8–12 inches of soil should be kept moist around trees during periods of drought, at least as far as the branches spread (dripline). The amount of water will vary with local weather conditions, but without adequate rainfall, even established trees may need watering as often as every 10–14 days. No matter which watering method is used, it is important that you don’t saturate the trunk. Instead, keep the surrounding soil evenly moist throughout dry periods.

Remember to water your trees during the growing months of the year. It is a necessity for newly planted trees, especially towards the end of summer on these hot, dry days, and in times of drought. Any questions can be directed to Village Forester Jon Yeater at 630-981-6285 or by e-mail at