1. Dig in!
Dig a hole twice as wide as the root ball and slightly shallower than the root ball.
2. Roughen the soil
If your planting hole has slick sides, roughen the sides and bottom with a pick or shovel. This makes it easier for root tips to penetrate into the native soil.
3. Remove the container
Be gentle but firm when removing the container from your tree. Making sure to protect the foliage, lay the tree on its side with the container end near the planting hole. Hit the bottom and sides of the container until the root ball is loosened. Slide the pot off the root ball and gently lower the tree into the hole.
4. Separate the roots
Check the root ball for circling roots. If circling roots are left in place near the trunk, they will cut into the trunk as the trunk's girth expands. Gently uncurl and straighten the roots so that they are going outward from the trunk. If a circling root is too stiff to move, you may need to cut it off, but be careful not to cut off too much of the root ball. If cutting circling roots will account for too much of the root ball, wait a year so that more roots will have grown. Do this quickly and shade the tree roots from the sun, so they don’t dry out and die.
5. Don’t bury the trunk
If soil covers the base of the trunk, it will lead to rot. Aim to have the top of the root ball about 1/2 to 1 inch above the surrounding soil surface, making sure not to cover it with soil unless roots are exposed. Adjust the hole depth by lifting the tree out of the hole (lift it by the root ball, not by the trunk) and adjusting the soil level in the planting hole.
6. Orient the tree
Orient the tree while you have the chance. Situate it so that branches won’t be in the way of pedestrian or car traffic. If you prefer a particular side of the tree, turn it toward a prominent viewpoint (such as your kitchen window). In sunny areas, orient the tree so that the best-shaded side of the trunk faces southwest. When turning the tree, lift it from the base of the root ball, not from the base of the trunk.
7. Make sure it's upright
Once the tree is in the hole, stand back and make sure it’s standing upright. Tilt the root ball until the tree is straight, then backfill firmly under and around the root ball.
8. Give your soil a boost
If your native soil is hard to work with (e.g., heavy clay) or retains little moisture (e.g., very sandy), you can treat it to some organic amendment, such as compost. The amendment won’t be a permanent solution to soil deficiencies, but it will help retain water and air in the soil around the root ball for the first few vital years. If adding soil amendment, always mix it with soil from the planting site; about one part amendment to three parts native soil is a good proportion for backfill soil.
9. Pack the soil
Pack down the soil as you backfill. Using the heel of your foot or the handle end of the shovel, press down firmly to collapse any large air pockets in the soil. This will help stabilize the tree in the hole. Don’t wait until the planting is finished; press down every few shovels of soil.
10. Water!
Build a watering basin around the root ball by creating a berm a little larger than the root ball perimeter. This concentrates water to the root ball. A tree that has a dry root ball can stand in a moist backfill without absorbing water. You'll need to water your tree thoroughly after planting with about 15 gallons of water. Monitor your tree's water needs at least once a week for the first month. This will give you an idea as to the frequency your tree will need water growing in your particular soil.
11. Only stake if necessary
Stake the tree loosely for protection or support if needed (if you are in a windy area or the tree is vulnerable to foot traffice/machines). Use only soft, pliable tree ties. Do not use wire, even if it's inside a hose; wire can cut into a trunk. If the trunk can’t stand up on its own, stake it so that it stands upright. The stakes should be placed outside of the root ball. Plan to remove stakes as soon as the tree can support itself, in 6 to 12 months.
12. Mulch
Cover the entire planting area with a 3 to 4-inch layer of mulch, but keep it 2 inches from the base of the trunk. Mulch keeps the topsoil temperate for root growth, reduces surface evaporation of water, slows or stops weed and grass growth around the tree’s base, and prevents a hard crust from forming on the soil surface.