A great time-saver for irrigating newly planted trees is to use a recycled 5-gallon plastic bucket. These are often discarded at construction sites. You first need to drill one or two 1/32 inch or smaller holes towards one side of the bottom of the bucket. Set it next to your small tree and fill with water every one to two weeks. You may move it to the opposite side of the tree each time you refill it. Gravity does the remainder of the work for you. If you have a row of seedling trees for a new windbreak, you can refill your water buckets from a tractor water tank if you have one. The idea may be adapted to irrigate shrubs or tomatoes while you're on vacation, too.