Planting Trees
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When done properly, adding trees to your landscape can not only add color, texture and shape, but it can increase the value of your property as well.
When to Plant
Generally accepted practice is to plant trees in fall or spring. It is less common knowledge that trees can be planted throughout the year, with exception of a very hot and dry season, particularly if they are balled and burlapped or container-grown trees. Fall planting provides a slight advantage by allowing for strong root development in fall months. While the above-ground portion of a tree stops growing and goes into dormancy, roots will grow and develop throughout the fall, and possibly winter, as long as the ground does not freeze.
Planting Considerations
Prior to planting, there are several things to consider – the type of soil, its chemical and physical characteristics, and the soil’s drainage properties. Trees and shrubs must be planted at the proper depth to thrive. In well-drained soils, trees and shrubs are planted as deep as the height of the root ball, or to the point where the roots start to flair.
However, West Virginia has predominantly clay soils notorious for poor drainage (Figure 1). This is the leading cause of many landscape problems, such as poor root development, lack of anchoring, overall weakness, and lack of performance due to suffocation (asphyxia) and/or root and collar rots (Figure 2).
Figure 1. Poor drainage. Photo credit: M. Danilovich
Figure 2. Asphyxia-dead root due to lack of oxygen. Photo credit: M. Danilovich
In a situation like this, the best approach would be to create a raised bed that would be about 12 inches above the existing grade to prevent roots from drowning.
Another approach would be to create a platform or pedestal and a dry-well next to the planting hole (Figure 3). The side of the hole must be scored to facilitate easier root penetration into the surrounding soil. If the sides are not scored but left smooth, the planting hole would be no different than a glazed clay pot. One the roots hit the sides, unable to penetrate, they would start to coil and wrap around, bounding and girdling themselves. The pedestal should be 8 to 10 inches above the bottom of the hole. Soil below the root ball should not be disturbed. Instead, dig around it to prevent soil from settling down and pulling the root ball down. Place the root ball on the pedestal and fill the bottom around it with crashed stone or gravel to absorb the access water away from the root ball. In soils with very poor drainage, this might not be enough, and a drywell may need to be added.
Figure 3. Improving drainage by creating pedestal and a dry well. Graphic/photo: M. Danilovich
Container-grown Trees
Trees grown in containers should be removed from them and placed directly into the hole. Any dead or damaged roots need to be pruned back. Any girdling roots must be cut, so they do not strangle the tree. The best way to deal with it, is to make four cuts through the root ball, about one to two inches deep, to prevent any potential circular root motion.
Balled-and-burlapped Trees
If trees come as balled-and-burlapped, then any effort must be made to remove the twines and as much of a burlap as possible regardless of whether the burlap is made of natural or plastic material. After positioning a ball in the hole, roll down the burlap and cut away. If needed, lean the ball on one side to cut material away as much as possible. If the burlap is of natural, organic origin, it will eventually decompose. However, if left on the ball, it will still restrict the root growth and act as a wick, pulling the moisture away from the roots and causing them to dry out and die (Figure 5). Plastic burlap, on the other hand, will not break down and decompose. It will act as a pot and continue to significantly restrict roots from growing and cause them to coil, girdle and eventually, kill the tree.
Figure 4. Cutting through the root ball to prevent coiling and girdling root. Graphic: M. Danilovich
Figure 5. B&B tree declining due to twines and burlap not being removed. Photos: M. Danilovich
Bare-root Trees
When working with bare-root trees, dig a hole large enough to accommodate all roots without having to prune them back or fold them to fit into the hole. Remove all damaged or dead roots, spread them evenly around the hole and start backfilling. The best material for backfilling is the original soil with 20% to 30% added compost or aged wood chips. When planting in poorly drained soils, sphagnum moss is not the best choice. It acts as a sponge and holds too much water, leading to root rot and tree death. Wood chips are much better choice, allowing for better and faster drainage.
Halfway through filling the hole, tamp the soil around so it has a good contact with the roots. Once the hole is filled, tamp the soil (Figure 6) to firm it up around the tree base and construct a 3-inch water-holding ring the size of a root ball diameter.
After planting is done, pour a bucket (or more, depending on a size of the tree and its root ball) of water to push any air bubbles out and provide good root contact with the soil. The raised water ring will keep the water on the root ball. As a final touch, 3 to 4 inches of mulch should be added to prevent soil moisture loss, keep the weeds away, moderate the soil temperature and provide some organic matter once it decomposes. When applying mulch, keep the mulch about 2 inches away from the base of a tree to prevent trunk rotting.
Figure 6. Tamping the soil around the planted tree to ensure good soil contact with the roots.
Author: Mira Bulatovic-Danilovich, WVU Extension Consumer Horticulture Specialist
Last reviewed: November 2022