Watering your tree
Part three of the “Taking Care of New Trees” Series is the Watering Your Tree.
Here is some good information pulled from Phytosphere:
Newly planted trees: Immediately after planting, all tree roots are in the original root ball area. Until new roots grow into the soil of the planting site, water the original root ball area and just beyond this area. The root ball area may dry out faster than the surrounding soil, so check the moisture in this area frequently for the first month or two after planting. See How to plant a new container-grown tree for more details on watering newly-planted trees.
A newly planted tree may take 1-2 years to become established. Larger container stock trees may take longer to become established than smaller stock.
For more information, visit their website here: http://www.phytosphere.com/vtf/treewater.htm