MASTER GARDENERS: Giving trees some tender loving care

Now is the time to give some TLC to your trees. Watering concepts for trees during drought are based on the type of tree, the soil, the best area to water, and the time and manner of watering.

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This summer the yard seemed to crackle when we walked. According to U.S. Climate Data, the average precipitation for Bemidji was 8.33 inches for the months of June and July. This year the rain gauge in our yard has only recorded about three inches of rain from June 1 to the last week in July. The U.S. Drought Monitor showed most of Beltrami County in extreme drought as of July 27.

Now is the time to give some TLC to your trees. Watering concepts for trees during drought are based on the type of tree, the soil, the best area to water, and the time and manner of watering.

The University of Minnesota Extension articles “Caring for Trees in Dry Weather” and “Watering Trees and Shrubs” provide excellent information and include a great YouTube video.

First, pulling weeds and applying mulch around trees helps them remain healthy. Mulch should be about three inches deep and go 12-18 inches from the base of the trunk to the edge of the tree canopy.

Second, determine if your soil is primarily sandy versus clay, silt or loam. If the soil is sandy, you may need to water every 3-4 days. If your soil doesn’t drain quickly and well, you may want to water more frequently for less time to let the water sink in.


Deciding whether supplemental water is needed can be done in two ways. First, does the tree have wilting, premature yellowing or dropping leaves? If so, it is time to water. Second, dig a small hole under the tree canopy. If the soil is cool and moist for about 6-9 inches, you don’t need to water, but if the soil is dry, water.

Third, watering should be done in the tree root spread area. Roots radiate like the sun’s rays; roots most responsible for water uptake are those small ones that are in the top 12-18 inches. A two-inch diameter tree with a circumference of 6-7 inches has a root spread diameter of about 12-14 feet. For a tree with greater than 16 inches diameter and circumference greater than 50 inches, the root spread diameter would be about 34-36 feet.

Fourth, for mature trees, if the top nine inches of soil are dry, use a sprinkler. Each week, mature trees need about 10 gallons per inch of trunk diameter. New trees should get about 20 gallons of water each week for 3-5 years. The water should get down to the root depth. Deciduous trees which develop shallow root systems, like birch, elm and maple, may need additional water.

Finally, water early in the morning to prevent water dispersal by wind and waste caused by evaporation. Overwatering can suffocate the roots.

Supplemental watering can be vital for tree health, especially for young trees. Water makes up a large portion of the wood and tissues in a growing tree; it aids photosynthesis and helps form leaves, buds and flowers. Watering during drought is crucial and should be continued until freeze-up.

These local garden articles will reach you each week throughout the gardening season, but gardening information can be found year-round by clicking on "Yard and Garden” at the University of Minnesota Extension website, , or by visiting our Facebook page at .

Local Master Gardeners will respond to questions via voicemail. Call (218) 444-7916 , and leave your name, number and question.

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