For a tree that will provide privacy hedging and grow incredibly fast, consider a hybrid salix. This hybrid willow has a growth rate of 6 to 12 feet per year and may reach its mature height of 40 feet within five years. Hybrid salix is a disease-resistant and cold-hardy tree that can withstand high winds and harsh conditions. Commonly planted as a wind-break and privacy hedge, it is generally available commercially as 2- to 3-foot trees in nursery pots. Plant the hybrid salix six weeks before the first frost. Hybrid salix trees are hardy to USDA zones 3 to 8.
Til the soil in the planting area to a depth of 12 inches. Break up the soil with a shovel or gardening fork so that it is loose and airy.
Dig a hole twice the width and depth of the tree's root ball, using the depth and width of the pot as a guide if it is potted. Scrape the sides and bottom of the hole with a garden fork to allow the roots better penetration. Place multiple plants no less than 3 feet apart for a dense hedge and 5 feet apart for a looser formation.
Add a 4-inch layer of compost to the soil that was removed when digging the hole. Mix it in well.
Place the roots of the hybrid salix tree into the hole. Plant it at the same depth as it has been growing in its pot. Add more soil if necessary to get the tree to the proper depth. Look for the soil ring toward the lower end of the trunk as a guide if the tree is bare root.
Cover the roots with soil. Fill the hole with water to settle the soil around the roots and to remove air pockets. Refill the hole with soil when the water drains.
Water the hybrid salix until the soil is saturated. Add a 4-inch thick layer of mulch, 2 inches from the trunk, and spread it around the tree to a distance of 8 inches after the water has drained.
Water the tree enough to keep the soil moist until the tree is well-established. This generally takes six to eight weeks.