Choosing a Planting Site & Planting your Tree
When choosing a planting site for your tree, be sure to consider the following:
- Think about the Future
Most of our trees are large shade trees that do well in full sun. Do not situate them too close to your home if you are concerned about branches hanging over your roof, driveway, etc. If you are planting to create shade for a deck remember that the sun changes position in the sky during the year and where a shadow is cast by a tree in mid-June is not where it will be in early September.
- Utility Right of Ways
Take into consideration the location of both above-ground and underground power lines and utilities. The power company owns the right-of-way under and around power lines that run through your yard. They can and will prune trees and shrubs if needed to prevent power outages, and you will not like their pruning.
- Loosen compacted soil
The soil around your home may have been compacted by heavy machinery when it was built. This will make it more difficult for roots to grow, so to alleviate this problem, dig the hole larger and deeper to loosen up the soil. Break up the excavated soil, then use it to fill in around the newly planted tree or shrub.
- Match the plant to the site
Low spots or areas at the base of a hill probably hold more moisture than hilltop or higher areas. Some plants, like buttonbush, require fairly wet conditions to grow their best and would be unsuited for a dry, sunny area at the top of a hill. A quick internet search or a question posed to your local nurseryman can help match the plant to the appropriate site. Also, some of our trees are understory trees which means they appreciate shade during part of the day; generally in the afternoon. Again, check with nurseryman to help get a perfect match.
Preparing the planting hole
Once your planting site has been selected, dig the hole 50% wider and deeper than the container the tree was grown in. Use your shovel to break up the excavated soil to eliminate larger chunks; finer soil is better. Begin by putting a few inches of this fine soil back into the hole. Adding sphagnum peat moss to this fine soil will help to increase moisture retention. With the tree still in its pot, place it into the hole to test how deep the tree will sit when planted. If the tree is too low, remove it from the hole and add enough fine soil bring it up to level with the landscape grade. If it is too high, then remove some fine soil. Be certain that the level of soil in the pot is even with the level of the soil in your landscape. In other words, do not plant the tree too deep or too high in the hole; you want the landscape grade to be level with the top layer of potting mix in the container. Once you are satisfied remove the pot from the tree and examine the roots as outlined below.
Pruning the Roots
An inherent drawback to growing trees in containers is that the roots are not free to roam. Instead, they are confined within a plastic pot and, when they grow to the edge of the pot, they begin to circle inside potentially becoming potbound. This can ultimately be a lethal problem but is easily remedied with a little bit of root pruning. When you remove the tree from the pot you may find that the roots surround the potting mix especially at the bottom of the pot. This is the beginning of being potbound. Using a sharp knife or pruners make a shallow cut (1/2” deep) through these roots at the bottom at 12:00, 4:00 and 8:00 (See Figure 1) The cut goes all the way through these roots which may resemble spaghetti in size and in color. Yes, you will be cutting roots a little bit but that is the idea. The new roots that will invade your soil and anchor your tree will start to grow immediately from the pruned root tips. Many, or all, of the circling roots will have been cut and they now will be able to grow as they should if the seed had been sown naturally. In many cases this is an unnecessary step but a quick look by you and a small nip-and-tuck if necessary will help produce a better root system.
Now the tree is ready to be placed into the hole and backfilled with the fine excavated soil/sphagnum mixture. Do not place large chunks of soil into the hole as these will not give purchase to the roots and will accelerate their drying out when droughts occur. Soil is the perfect environment for roots; it insulates against extremes of temperature and water loss. The roots, however, need to be in contact with it in order for these qualities to work. Large chunks of soil minimize the contact area roots have with soil and hold less moisture. Moisture also has a harder time moving laterally through the soil if there are large, underground air spaces created by chunks of soil.
Once the hole has been backfilled tamp it down gently with your foot and water in well. In a few days check to see if the soil has settled and add more soil if necessary to regrade around the trunk. Apply liquid feed fertilizer if you are planting in spring or summer; just plain water if you are planting in the fall. See our fact sheet on fertilizing your trees for complete information.
A word about mulch
Mulching around a tree is a good idea unless it is taken too far. The purpose of mulch is to help the soil retain moisture. If mulch is applied in a thick layer, it can actually cause the roots to grow upward in search of moisture. In such cases, the roots can wrap around the trunk and slowly strangle the tree as they grow thicker. Mulch only needs to be applied a couple inches thick and should not come in contact with the trunkDeep mulch also allows gnawing rodents a protected pathway to damage bark at the base of trees and shrubs so no more than a few inches is all you need. . Do not mound the mulch around the trunk like a volcano. This is definitely a no-no.
If you are worried about weeds growing through the mulch a commercial weed fabric can be used to keep them under control. Consider though, that weed fabric will prevent the movement of insects, worms and other beneficial organism through the soil profile. It will prevent some moths from digging a shallow chamber in which to pupate. So if you went to all the trouble to plant trees that would attract them your efforts will be hampered if the caterpillar cannot dig through the weed fabric and complete its life cycle.
Spraying a pre-emergent herbicide a day prior to mulching followed by a layer of good quality mulch will help keep weeds down and allow animals access to the soil. Do not allow herbicide spray or drift to come in contact with the tree; especially the leaves. The trunk will not suffer adverse effects if it does but it is a good idea not to let it happen in the first place.
If you ever walked in a forest you have probably noticed that weeds are not generally as big a problem in the middle as they are on the edge. This has to do with light competition primarily but the fallen leaves themselves act as a barrier to some invasive plants becoming established. In the fall consider leaving your leaves where they fall as a natural mulch. A layer of decaying leaves will help retain moisture too while providing a timed release fertilizer. Some moth species, like Luna Moths pupate in the leaf litter beneath the tree they fed upon. If you dispose of these leaves or grind them up with a mower you will kill the pupa. If you must collect the leaves why distribute them back into your flowerbeds, garden and around your trees. This way, any overwintering organisms will be allowed to complete their life cycle.