Water is the single most important element as plants acclimate to their new surroundings. It’s best to use a soaker hose, drip irrigation or a slow trickle from the garden hose to get water down to the depth of the root ball and all the way around the roots. Do not rely on your sprinkler system to provide all the water without checking first. Also, some plants get more water than they need because two or three different sprinkler heads are hitting them, especially trees planted in turf areas. Remember that roots need water AND oxygen, and if there is too much water the plants can actually drown. Overwatering is a common (and often fatal) mistake, so water with care. As a general rule, plants that are too wet will start looking yellow without wilting or dropping leaves. Plants that are too dry almost always have leaves that look wilted and eventually get a crispy appearance then drop off.
Water During the First 1-2 Months
Start by checking for moisture under the mulch at the base of the plant on a daily basis, especially during hot, windy weather. Once you have an idea how much water each plant requires, a visual inspection every few days should be adequate.
Soil type will affect your watering schedule because clay soil holds moisture longer than sandy loam. In general, during the spring and fall, water newly planted trees and shrubs every 3-4 days for sandy loam soil or every 4-5 days for clay soil. During hot, dry periods in the summer, water every 2-3 days for sandy loam or every 3-4 days for clay soil. Before watering, be sure to check the soil moisture by pushing your finger down into the soil a few inches.
Sometimes, newly planted broadleaf shrubs may defoliate during July and August. It is critical to continue watering these plants as stated above. As the weather cools in the fall, the plants will releaf.
Water During the Remainder of the First Growing Season
Starting with the third month and continuing through fall, water about once a week unless we are experiencing very hot temperatures. Then you may need to water twice a week. If the fall months are dry, make sure plants are watered thoroughly going into the winter. Then take advantage of warm days to water every couple of weeks if we continue to have little or no winter precipitation.