Spring and fall are the best times to plant a tree. This allows the tree to grow roots before the freezing of winter or intense heat of summer.
How to plant a balled or burlapped tree
What is a balled or burlapped tree? The tree roots are wrapped in burlap or plastic that looks like a big ball at the bottom of the tree. Burlap helps keep the soil around the roots when the tree is being moved.
Dig the hole. It should be as deep as the soil in the ball. The width of the hole should be at least three times the width of the ball. Loosen the edges of the hole, especially the bottom. This will help the new roots to grow easily.
Pick up the tree by the ball and place it in the hole. Never carry the tree by the trunk, because the weight of the ball will shift causing the roots to break.
Place the tree in the hole and arrange it in the center.
Remove the burlap or plastic from the ball.
Make sure the tree is standing straight, then backfill the rest of the hole with a combination of earth from the hole, peat moss, and composted manure. Do not compress the backfill. The backfill should not go any higher up the trunk than the root ball.
If your tree is three feet or taller, you should stake it so it doesn't start to lean over as the soil settles. See diagram.
Water the tree very well every day for the next few weeks. Later you can water every week or so, depending on your climate.
Planting bare-rooted trees
Planting bare-rooted trees is a little different from planting balled trees. For one thing, bare-root trees will dry out quickly, so you have to make sure the roots don't dry out. Another thing is that the roots should be carefully trimmed to remove any damaged roots. Just trim them back to the healthy roots. Save as much of the healthy root system as you can.
Dig a small hole and make a cone of dirt in the bottom of the hole.
Place the tree in the hole and spread the roots of the tree evenly around the cone. Make sure the crown, where the roots met the trunk, is about two inches above the top of the soil. See illustration.
Hold the tree so it is straight, and backfill as above.
Water every day for the next few weeks. Later you can water every week or so, depending on your climate.
Where to get trees
Aside from your local nursery or discount store, there are a number of places that will send you small trees for very little money. FreeTreesandPlants.com distributes overstock trees from other companies for just the cost of shipping. The Arbor Day Foundation sends 10 free trees with a $10 membership. Finally, your state department of conservation or forestry agency may offer free or inexpensive trees.