Holes for trees should be dug to the depth of the existing container or soil ball. Holes should be 1 ½ to 2 times the diameter of the container or soil ball. Trees in containers sometimes have several layers of roots on the sides and bottom of the soil ball. Loosen roots or slice through them with a knife to redirect growth downward and outward rather than around and around. Trees should be planted at the same depth they are growing or slightly higher. Do not cover the top of the soil ball. It should be at the same level as the existing soil or up to an inch above. If tree roots are wrapped in burlap and tied with twine, cut and remove twine after placing the tree in the hole. Fold the burlap back off the top of the soil ball into the hole. Tree trunks of large trees are sometimes wrapped to protect them during shipment. This wrap should be removed as soon as the tree is planted.
Fertilizer can be added as you fill the soil around the roots. I use a general purpose fertilizer such as 16-16-16 or lawn fertilizer. After planting, a one to two inch layer of bark dust or compost can be added on top to act as mulch. Weed barrier fabric can be applied before the mulch if desired. Keep an area at least 3 feet in diameter around the tree free from grass and weeds. This area should be increased in size as the tree grows. Trees will grow at twice the rate if there is no grass competing for water and fertilizer. This also protects the tree trunk from damage caused by mowers and trimmers. Trimming grass around young trees with a line trimmer can severely stunt or even kill them.
Trees less than 6 feet tall generally do not need to be staked unless you live in a windy area. For larger trees, use one or two tree stakes 2 inches in diameter and 6 to 8 feet tall. Pound stakes into the soil up to 2 feet deep. If you use twine to fasten trees to a stake make the loop around the tree at least 3 times the diameter of the trunk or fasten it to a flexible tree strap. Twine can cut into the bark as the tree moves leaving a weak area which can snap easily in a storm. Plastic chain link tree fasteners are safe and easy to use. Ties should be somewhat loose so the tree can move with the wind. If trees are fastened so tight that they can’t move, they will not develop the trunk strength needed to survive on their own.
Trees need to be staked for only one year. If you plant trees this spring, remove the stakes next spring. Occasionally stakes are left for 2 years in very windy areas. Check periodically to make sure fasteners are not becoming too tight as the tree grows. Loosen as needed to assure tree movement.
The only reason to prune a newly planted tree is to remove a broken branch or correct growth defects. If a tree has two or more competing leaders at the top, shorten all but one. If small branches develop on the lower tree trunk, do not remove them. If allowed to remain for 2 or 3 years, they will increase the growth rate of the trunk diameter. Just shorten them so they do not become more than 6 to 10 inches long.
Trees need frequent irrigation during their first growing season. Light sprinkling will not reach the full depth of the root system. Place a soil mound in a circle to create a saucer to hold water. Fill the saucer at least an inch or two deep each time you water. Water every 2 to 3 days for the first two weeks and once a week for the first summer. If trees are planted in an area with sprinkler irrigation, supplement with deep watering periodically.