Plant Trees Properly, and They Thrive
One of the most common factors that is overlooked concerning the health of trees is how they are planted. Correct planting can maximize growth rates, make proper watering easier and significantly increase disease and pest resistance. Trees are usually purchased from garden centers and are grown in plastic pots. These are generally referred to as containerized trees. However, in late winter and early spring, bare-root trees are also available. These have been harvested from the ground the previous fall and have had most of the soil washed from the roots.
Many of the same principles apply when planting either kind of tree. For instance, planting a tree too deeply can allow too much water to enter the root-ball, which causes the roots to rot. Another common mistake is placing trees in lawn areas. Irrigation requirements are different for each and trying to maintain both in the same vicinity can be tricky. Ideally, trees should be placed in separate beds, but planting them in turf is sometimes unavoidable. As a rule, sod should never be placed back over the top of a root-ball (Fig. 1). This makes it more difficult to determine how much water a tree is receiving, makes the tree more susceptible to damage from mowers and trimmers, and puts turf and trees unnecessarily in direct competition for nutrients (Fig. 2).
To plant bare-root trees, cut off any damaged roots just beyond the point of damage with sharp pruning shears and prune damaged branches back to a major branch intersection or to the trunk. After doing this, soak the roots in a bucket of water for 3-6 hours before planting. When you are ready to plant, dig the hole just below the tree’s root collar and twice as wide as the root-ball. After digging, place a cone shaped mound of soil in the middle of the hole and gently spread the roots over the mound (Fig. 4). Gently tamp the soil, being careful not to damage the roots. Remember, you want the soil to be somewhat firm but not like cement. Bare-root trees should always be staked from two or three sides for 1 year after they are planted. When attaching rope to the tree trunk, be very careful to avoid damage by first wrapping an old cotton cloth multiple times at the point where the rope is to be attached (Fig. 3). This protects the bark from rubbing action caused by the wind.
When planting containerized trees, dig the hole as deep as the root-ball contained in the pot and not the pot itself. The hole should be at least 6 inches wider than the root-ball on all sides. Position the tree in the hole and place the soil back around the root-ball. When placed back into the hole, soil should be firm, but not so compacted that it inhibits water penetration. Soil should also not be placed over the top of the root-ball. Containerized trees do not always need to be staked. However, larger trees and trees planted in excessively windy areas may benefit from staking (Fig. 5). Never leave trees staked for more than 1 year and follow staking procedures mentioned previously.
A question often asked is whether trees should have organic matter incorporated into the soil that is placed around the roots. The answer is generally no unless the particular soil has drainage problems. If this is the case, mix three parts soil to one part coarse organic matter (not peat moss), and incorporate this mixture back around the root-ball. Plant bare-root trees so that the root collar is 1 to 2 inches above ground level and slope soil away from the root collar (Fig. 6). The same holds true for containerized trees where the actual root-ball should be raised 2 inches above ground level (Fig. 7).
After planting either type of tree, it is acceptable to place a ring of soil around the root-ball to make it easier to deep water plants. This should be done so that water penetrates to the bottom of the root-ball. Check the soil periodically and when it starts to dry, deep soak the plant again. All soils are different and there is no exact science dictating how often to irrigate. Over-watering is a very common way that plants are killed. It will take one to two growing seasons to establish your plants.