The primary concern for new trees is adequate access to water. There is no one-size-fits-all approach to watering. Keep the soil and mulch moist, but not soggy. If there is standing water around the base of the tree it has been overwatered. Overwatering saturates soil and deprives the roots of oxygen, if the condition persists it can kill the tree.
The boulevard trees planted by the city are known as containerized trees as they come from nurseries in plastic pots. These young containerized trees lose most of the water their root ball was holding to the surrounding soil during the planting process. While location, weather, and soil conditions should always be considered, containerized trees - both deciduous and evergreen - require frequent watering after planting. Having adequate water early in the growing season is essential for root expansion as they actively seek out and grow into moist soil, increasing their anchorage and providing important nutrients for growth.
Newly planted trees require a complete soaking every 7 to 10 days from the time of planting until winter temperatures arrive in the late fall and the ground begins to freeze.
During hot/dry summers newly planted trees and those put to ground within the last 5 years need more frequent watering, every 3 to 5 days.
Do not apply lawn chemicals of any kind on the boulevard strip where trees are planted.
Never use a weed-whip trimmer around young trees, damages to the trunk at a young age often result in tree decline/failure.
The most sensitive part of any tree is its root system. Protect them from cold Minnesota winters by mulching in the late fall - before the ground freezes.