If you planted new trees this spring or last fall, bring out the garden hose. A little water will keep those trees healthy and happy as Michigan’s dry spring progresses into summer.
“Abnormally hot and dry conditions mean your newly planted trees are probably thirsty,” said Kevin Sayers, Urban and Community Forestry Program manager with the Michigan Department of Natural Resources. “Make sure any trees planted in the past year are getting at least 10 to 20 gallons of water a week until regular precipitation returns. Your trees will appreciate the drink.”
New trees, especially, are still setting their roots and need water, Sayers said. However, dry weather also can weaken healthy trees and make them more vulnerable to disease, insect damage or winter breakage.
Deciduous trees – those that lose their leaves in fall – show drought stress through curling or drooping leaves. Leaves may “scorch,” or turn brown at the margins, fall off early or exhibit early fall color. Evergreen needles may turn yellow, then red or brown.
It’s important to water trees correctly. When watering, prioritize newly planted or high-value trees. Water newly established trees weekly and established trees every two to three weeks. A long, slow soak under the tree’s dripline, the ground where branches extend over, is best, so soil is saturated at least 10 to 12 inches deep. Once a week is generally enough. Overwatering can create problems too, so if soil under the tree is moist, you don’t need to add more water.
Mulch also helps retain soil moisture and save water. Apply 3 to 4 inches of organic mulch under the tree canopy, around but not touching the base of the trunk. You want the finished mulch pile to look like a doughnut, not a volcano.
Watering tips
Sprinkler: Place an empty container or rain gauge nearby to measure about 1 inch of irrigation.
Hand watering via hose: Let water run slowly until the ground is saturated (10 to 12 inches deep) and moist near the base of small trees or at various points under the dripline of large trees.
5-gallon bucket: Most newly planted trees need 5 to 10 gallons of water per inch of trunk diameter (at knee height) each week.
Soaker or trickle hoses: Saturate the soil under the dripline to at least 10 to 12 inches deep.
Don’t water during the middle of the day. Much of the water applied at the hottest or windiest time of day is immediately lost to evaporation.
Mist sprinklersaren’t effective for trees. As much as 70 percent of water may be lost to evaporation into the air.
Lay off the fertilizer. Fertilizer salts can cause root injury when soil moisture is limited.
Summer is a stressful time to plant trees, largely due to hot temperatures and the need for water. So, if you haven’t already planted, it may be best to wait until fall.
When conditions are right for planting, the DNR encourages Michigan residents to join the challenge of planting 50 million trees by 2030 and pin their new trees on an interactive map as part of the MI Trees challenge. Help ensure the future of conservation in our state – plant it forward!
