The answer depends on the age of the tree or shrub. Newly planted trees and shrubs need regular watering for approximately two years to help establish roots. Mature trees and shrubs native to Minnesota do not require frequent watering unless there are drought conditions. During long periods without rainfall, such as the drought in the summer of 2021, trees and shrubs may experience decline or die without supplemental irrigation. As changes in our climate patterns continue, this may become a more frequent need for homeowners to protect their landscape assets.
How often should I water a newly planted tree or shrub?
You will want to regularly water a new planting in the Minneapolis area until the root spread equals the spread of the above-ground canopy. While this can be hard to measure, a safe bet is to plan on watering your new planting for two years at the following intervals:
– Water daily for the first two weeks after planting.
– Water every 2-3 days for 3-12 weeks after planting
– After 12 weeks, water weekly until roots are established
How should I water trees and shrubs?
Our experts recommend one of the following methods below for watering. Follow the correct frequency for new plantings above or water weekly during drought for mature trees and shrubs.
- Use a Soaker Hose
Wrap the hose around the base of the tree at least 1-2 feet from the trunk. Turn the water on in the morning and let it run all day. Do this once a week during summer drought periods.
- Use a Garden Hose Set to Trickle
A trickle is more than a drip and less than a gurgle. Visually divide the area around your tree into four sections. Place the hose about 2-3 feet from the trunk in section one and let the water soak into the ground for about two hours. Move the hose to each section every two hours until you have thoroughly watered all four quadrants over a day. Repeat once a week during summer droughts.
- In-Ground Irrigation
Set your system to run an extra hour in the zones where you have trees and shrubs. This will allow the water to penetrate through the turf roots and thatch and allow more water to soak down to the roots of the trees. Be sure that the sprinkler heads are positioned so that they are not hitting the trunk of the tree.
Note: Overhead sprinklers are not recommended. Using the recommended soaking techniques, you saturate the grass in the spot where the hose is, enabling water to move beneath the root zone of the grass and get to the tree roots. Trees can die even when the grass is green because grass is the better competitor for water.
What happens if trees and shrubs don’t get enough water?
Trees and shrubs in the Minneapolis and St. Paul metro are more prone to drought damage and death than natural stands of trees and if they do not receive enough water are unable to create new growth. When this happens, root development is reduced, plant are more susceptible to insects and diseases, and response to wounding from pruning or breakage is limited. As trees and shrubs reach this stage, they start to shut down and become targets for diseases and insects that can kill them.
What if I think my trees or shrubs have damage due to drought?
One of our Certified Arborists can inspect your trees and shrubs to identify drought stress. Additionally, they can manage everything to keep your trees and shrubs healthy and looking their best. Contact us to schedule a consultation today!
Watering Drought Stressed Trees – Fact Sheet
Watering established trees and shrubs – UMN Extension
Watering newly planted trees and shrubs – UMN Extension