When trees are first planted, a berm can be erected around the base to provide targeted water to the developing roots. However, it should be sloped within the raised border to keep water away from the base of the tree. It must be removed after the first year as the roots will have outgrown the size of the well and water should be more widely applied to encourage continued expansion of the roots.
Improper tree well left too long
Regular water should be supplied the first two or three years, and should be applied slowly enough to infiltrate at least 18" to 2'. This can be checked with a soil probe, or even a long screwdriver.
In subsequent years, watering frequency can be scaled back to once or twice a month with a slow, deep watering. If trees are in beds with other plants that receive more frequent, shallow irrigation, it is advisable in the summer to provide a monthly slow, deep irrigation to
encourage the continued health of deeper roots. MULCH in the root zone kept a few inches from the trunk will help keep the soil moist while improving soil health and protecting roots from temperature changes.
Proper new tree berm construction