Trees: Planting a Tree
To properly plant a tree, go through the following steps:
- Look up. If there is a wire, security light, or building nearby that could interfere with proper development of the tree canopy as it grows, plant elsewhere.
- Dig a shallow planting hole as wide as possible. Shallow is better than deep! Many people plant trees too deep. A hole three times the width of the root ball is often recommended but about one-and-one-half the diameter is more common. Wider holes should be used for compacted soil and wet sites. This might help roots from becoming deformed by the edge of the hole in compacted or clayey soils. The depth of the hole should be LESS than the height of the root ball, especially in compacted or wet soil. If the hole was inadvertently dug too deep, add soil and compact it with your foot. Breaking up compacted soil in a large area (out to the dripline of the tree) around the tree provides the newly emerging roots room to expand into loose soil. This will hasten root growth translating into quicker establishment. Loosen the soil with a rototill, shovel, or other tools.
- Find the point where the top-most root emerges from the trunk. If this is buried in the root ball then remove enough soil from the top so the point where the top-most root emerges from the trunk is within the top two inches. A swelling (called trunk flare, root flare, root crown) may or may not be present where the top-most roots join the trunk. Check for and treat circling roots especially in the top half of the root ball. Soil above the top-most root may have to be removed to check for these. The point where the top-most roots emerge from the trunk can be exposed and visible.
- Slide the tree carefully into the planting hole. To avoid damage when setting the tree in the hole, lift the tree with straps or rope around the root ball, not by the trunk. Special strapping mechanisms need to be constructed to carefully lift trees out of large containers.
- Position the point where the top-most root emerges from the trunk slightly above the surface of the landscape soil. Most horticulturists agree that it is better to plant the tree a little high than to plant it too deep. If the tree is too deep in the hole, remove it from the hole and firmly pack soil in the bottom of the hole to raise the root ball. If it is only a little deep, tip the ball to one side and slide some soil under it; then tip it back the other way and slide some more soil under the ball. Continue this until it is set at the appropriate depth. Once it is at the appropriate depth, place a small amount of soil around the root ball to stabilize it. Soil amendments are usually of no benefit. The soil removed from the hole makes the best backfill unless the soil is terrible or contaminated. Cut roots that are kinked or any that circle the top of the root ball where appropriate. If these cut roots are large, the tree might shock and could die.
- Straighten the tree in the hole. Before you begin backfilling have someone view the tree from two directions perpendicular to each other to confirm the tree is straight. Fill in with some more backfill soil to secure the tree in the upright position. Once you add large amounts of backfill, it is difficult to reposition the tree.
- Remove all synthetic materials from around the trunk and root ball. String, rope, synthetic burlap, strapping, plastic, and other materials that will not decompose in the soil must be removed at planting. Some people attempt to remove some or all of the wire from wire baskets before backfilling; this may void any guarantee that came with the tree.
- Slice a shovel down into the backfill 20 to 30 times all around the tree as you add backfill soil. Attempt to break up clayey soil clumps as much as possible. Do NOT step firmly on the backfill soil because this could compact it and restrict root growth, especially in clayey soil. When the planting hole is filled with soil the root ball should remain 1 (small trees) to 3 (larger trees) inches above the backfill soil as shown in the photograph at left. Add 10 to 20 gallons of water to the root ball and backfill. Fill in any holes or depressions with additional backfill soil. Do not firmly pack backfill soil in an attempt to eliminate air pockets because this could cause too much soil compaction. The water infiltrating the backfill soil will eliminate the large air pockets. The presence of small air pockets could even be of benefit because they could allow more air to reach the roots.
- Cover the sides of the root ball with mulch and apply mulch to at least an 8 foot diameter circle around the tree. Construct a berm out of mulch at the edge of the root ball only if the tree will be watered with a hose, bucket, or other high volume means. Constructing a berm in all other situations will not provide more water to the root system. Do not construct a berm from soil since this soil could end up over the root ball several months later. Water the mulch well after it is spread.
- Stake the tree, if necessary to hold the root ball firm in the soil. If the root ball moves in the wind, emerging roots could break and trees will establish slowly. Staking to hold a weak trunk upright should not be necessary on trees with a trunk diameter more than about 1.5 inches. If large trees require staking to prevent the trunk from bending, it probably indicates a lesser quality tree. Smaller trees might require staking until enough trunk strength develops. Trees could establish more quickly and develop a slightly stronger trunk and root system if they are not staked at the time of planting.
- Regular irrigation after planting encourages rapid root growth that is essential for tree establishment. Follow these irrigation recommendations to promote vigor and survival.