Some nurseries raise trees in containers from the outset, and the first time they're ever in the ground and develop roots freely is when you plant them in your yard. Before you purchase a containerized tree or shrub, check to see if it's rootbound. Be suspicious if roots are swelling above the soil level, wrapped around the trunk, or trailing out the bottom of the container. Ask the salesperson to lift the plant out of its container so you can see if the roots are wrapped in circles around the soil ball. Choose a plant that's still comfortable in its pot. It will be less stressed and more willing to wait longer in case planting is delayed.
The idea is to encourage the tree's or shrub's roots to leave their pampered environment of loose, rich container soil and venture forth to find food and water on their own in a strange, more daunting soil. Don't put any special soil amendments in the hole or add them to the fill soil. They might encourage roots to stay put and wrap around themselves.
Withhold fertilizer, which mainly fuels foliage growth, while the tree or shrub concentrates on root growth. Once the planting is established and new stems and foliage appear, sprinkle some granular, slow-acting fertilizer over the root zone and let the rain soak it in. Use lots of organic mulch to keep the soil moist, and give the new tree or shrub plenty of moisture the first year or two. Water it in winter when the ground isn't frozen.
Fall is the best time to plant many trees and shrubs. But spring is the next best time to plant and transplant and is preferable for certain trees, such as oaks, beeches, birches, and willows. You can plant those that come in containers almost any time the soil isn't frozen.
1. Dig the planting hole just as deep as the tree's or shrub's container. Slope the sides a bit so the hole is wider near the top to encourage the roots to grow laterally outward into the soil.
2. Slide the root ball out of the container carefully. If the soil is moist, the ball should come out easily. If it's stubborn, check to see if roots protruding from the bottom of the pot are snagging it.
3. Loosen and untangle any circling or snarled roots. Cut any that are broken, dead, or hopelessly tangled. Those protruding from the soil ball will have a head start growing outward.
4. Loosen any bottom roots that have matted. If they don't free up easily, cut or slice through them to get them to hang freely. Cut off impenetrable masses. This won't harm the plant.
5. Set the plant in the empty hole. Step back to see if its orientation is pleasing. Then check its depth. The top of its soil ball should be even with, or slightly above, the surrounding ground.
6. Fill the hole with the plain dirt that you dug from it. Don't add materials to improve it unless the ground is solid clay. The plant has to learn to handle its new soil environment.
7. Firm the soil around the buried root ball to remove any air pockets. Create a watering basin by mounding the soil several inches high just beyond the edge of the planting hole.
8. Water the tree or shrub thoroughly, filling the reservoir, then letting it drain. Do this several times, waiting awhile between waterings for the water to soak in deeply.
9. Stake trees only if they are threatened by wind. Insert two or three stakes into the soil, equidistant around the root zone. Loop soft tie material around the trunk and tie one loosely to each stake.
10. Mulch the root zone with a 2- to 3-inch layer of organic material, such as aged wood chips, pine needles, or chopped leaves. Don't pile mulch against plant stems, and don't fertilize now.