Courtesy of the Wisconsin Department of Natural Resources
WISCONSIN – It’s been a warm summer already, and we are likely to see that hotter than average trend continue. It’s great for getting out on the water and enjoying the outdoors. It also means you, your pets, your plants, and yes, your trees, will need more water.
Stress from drought can affect all plants, from a newly planted sapling to a well-established, mature tree. Trees that are already weakened from other types of stress, such as tree leaf predation by spongy moths, are of particular concern.
When should I water my trees?
First, check to see if the ground needs watering. Stick your finger a few inches into the ground (or use a trowel) and feel how wet it is. If it feels dry, then water it. If it’s wet, lay off the watering for a bit. For other signals that you should water your trees, check out this tree watering article (www.bit.ly/3B6Gz1L).
Avoid watering during the hottest part of the day (10 a.m. to 6 p.m.). Otherwise, some of the water can evaporate before the plant can soak it up.
How often should I be watering my trees?
The amount of water depends on tree size, your soil type (sandy versus clay) and other factors.
Here are some suggested guidelines, but again always check beforehand if the soil is dry and needs water:
Newly planted trees need extra watering until they are established.
- 1-2 weeks after planting: daily watering may be necessary.
- 3-12 weeks after planting: generally, water every 2 to 3 days.
- After 12 weeks, water weekly.
See the University of Minnesota Extension’s Plant and Growing guides (www.bit.ly/3znTPhd) for more specific instructions.
Established trees will need to be watered around once a week. The University of Minnesota Extension also has a guide for watering established trees.
How much should I be watering my trees?
At planting, trees will need around five gallons of water. One easy way to do this is by filling a five-gallon bucket with five holes in the bottom and placing it where tree roots would be.
When in doubt, let your sprinkler run for an hour under each tree in your yard if there is not a soaking rain each week during the growing season (April through October).
Can I harm a tree by overwatering it?
If you have poorly drained soil (clay or compacted soil), it is possible to overwater. If the water can drain through the soil over the course of five to 20 hours, there is not likely to be an issue.
Root rot happens when water sits around the roots for over 24 hours because it has no way to percolate and flow through the soil (this happens to plants in pots without drainage holes).
What do drought conditions look like for my area?
If you are curious about current drought conditions in your area, you can find county-specific information on this map (www.drought.gov/states/wisconsin).
What else can I do to help my trees stay hydrated?
Adding organic mulches, like wood chips, around the tree base helps to retain moisture and keep roots cool. Page 13 of the Tree Owner’s Manual (www.bit.ly/3PSu51X) provides an excellent visual of what mulch should look like.