Check soil moisture of newly planted trees and shrubs at least once a week. Soil that is moist or damp to the touch is fine. If the soil begins to dry out, water the plant thoroughly. Do not overwater; however, you can easily drown newly planted trees and shrubs through too much tender loving care with the hose.
You can maximize growth of new trees and shrubs by having a mulched area instead of grass under the plants. This reduces competition for nutrients and moisture. Apply mulch as far out as the spread of the branches but no more than two - three inches in thickness. Mulch should never touch the bark of the plant!
Newly planted trees do not benefit from fertilizer. During the establishment period (up to two years) root growth is more important than top growth. Mature trees also do not need fertilizer because as trees age and mature the growth process slows down. In the landscape, woody plants receive nutrients from lawn fertilizer if their roots are adjacent to or growing in turf areas. And nutrients are provided by decomposing organic matter such as fallen leaves, decaying mulch, and minerals in the soil.