Part two of Mike Barhorst’s recent column: Ideally, trees are planted during their dormant season — in the fall after their leaves drop or in early spring before budbreak. Weather conditions are cool and allow plants to establish roots in the new location before spring rains and summer heat stimulate new top growth. Healthy, balled and burlapped or container trees can be planted throughout the growing season if they are given appropriate care.
Urban soils can be especially difficult, particularly in areas of newer construction. Top soil is often removed or mixed with subsoil. In addition, the soil may have high acid or high alkaline content. Testing the soil in advance is helpful. As State Forester Wendi Van Buren will tell you, the “recipe” is even more helpful.
The “recipe” includes the following steps. Once you have chosen the right tree for the right space, it is time to begin digging the hole. Dig a broad planting hole, two to three times wider than the root ball. However, it should only be dug as deep as the root ball. Digging a broad planting pit breaks up the surrounding soil and provides newly emerging tree roots room to expand.
Identify the tree’s trunk flare. The trunk flare is where the trunk expands at the base of the tree. This point should be at least partially visible after the tree has been planted. If necessary, remove the excess soil from the top of the root ball prior to planting if the root flare is not visible.
Next, remove the container, the burlap or cut away the wire basket. Inspect container tree root balls for circling roots, something that will happen if the tree has been in the container too long. Straighten, cut, or remove the circling roots.
The majority of a tree’s roots develop in the top 12 inches of soil. If the tree is planted too deep, new roots will have difficulty developing, in part because of the lack of oxygen. In poorly drained or heavily clayed soils, trees can be planted with the base of the trunk flare two to three inches above ground. When placing the tree in the hole, it is important to lift the tree by the root ball, not the trunk.
Make certain to straighten the tree in the hole before placing dirt around the tree. Either you or someone else needs to look at the tree from several directions to confirm that it has been placed in the hole properly. Once the tree has been planted, it is nearly impossible to reposition the tree.
Back fill the hole gently, but firmly, utilizing the soil you removed from the hole earlier. Pack soil around the base of the root ball to stabilize it. As noted above, if there is anything remaining around the root ball be it burlap, plastic, string or wire, remove it before backfilling the hole. This will facilitate root growth.
Fill the remainder of the hole, firmly packing the soil to eliminate air pockets that may dry out roots. Air pockets can be eliminated by watering periodically while backfilling. Do not fertilize the tree at the time of planting.
If necessary, stake the tree. While studies have shown that trees establish more quickly and develop stronger trunk and root systems if they are not staked at the time of planting, staking may be required if you are planting bare root stock or planting on a windy site. Stakes may also offer protection against lawn mower damage. If you stake the tree, make certain to remove the stake one year after planting.
Mulch the base of the tree. Mulch is organic matter spread around the base of a tree. It helps hold moisture, moderates soil temperature extremes, and reduces grass and weed competition. Common mulches include leaf litter, pine straw, shredded bark, peat moss, or composted wood chips. A two to four inch layer is ideal.
More than four inches of mulch may cause problems with oxygen and moisture levels. Piling mulch right up against the trunk of a tree may cause decay of the living bark. A mulch free area, one to two inches around the base of the tree, reduces moist bark conditions and prevents decay.
One of the things I have noticed in Sidney (and elsewhere, for that matter) is the tendency to pile mulch in a pyramid around the base of the tree. This is referred to as volcano mulching.
Volcano mulching is an improper mulching technique where mulch is piled high against the trunk of a tree. Mulch should not touch the trunk of the tree. The trunk is simply not meant to be covered, and doing so invites improper root growth, decay and pests; it may kill the tree.
Once your tree has been planted, provide the necessary care the tree needs, especially in the first couple of years. Keep the soil moist, but not waterlogged. If it doesn’t rain, water newly-planted trees at least once each week. You may have to water the tree more frequently in hot, dry windy weather. If the soil below the surface of the mulch is dry, it is time to water.
Consideration should be given to using a “gator bag” for your trees. Especially if you are going to be traveling, gator bags can provide enough water for a week or more during the heat of summer.
You may also need to prune branches that are either damaged during the planting process, or die following the planting process. You should prune sparingly after planting and delay necessary corrective pruning until after a full growing season in the new location.
If you follow these steps, it will make it more likely that your newly planted tree will not only grow, but thrive in its new location. I plan to plant a tree at my home this year. The new tree will replace the ash tree that, despite years of treatment, finally succumbed to the emerald ash borer. I would encourage you to consider planting a tree as well.
The writer is the mayor of Sidney.