How to Plant a Tree

Audrey Hillman
Adams County, Penna. Master Gardener

On a recent trip to Seattle my husband and I flew over parts of Montana where the wild fires were visible from the plane. It was easier to understand the scale of the destruction when viewed from 23,000 feet than when seen on TV. It started me thinking about the value of what was being lost, especially the trees. Although fire can be essential in the process of revitalization, it takes a long time for a forest to recover. It made me realize how much I value the trees in my own yard.

As I watch the aging process in my trees, I am busy planning the placement of new young trees that in the years to come will continue to provide all the benefits I now enjoy in my mature trees. They help to settle out, and hold, dust and smoke. Trees absorb carbon dioxide produced from motor vehicles and, in return, produce oxygen, helping to reduce both the greenhouse effect and global warming. They provide food and cover for wildlife, which, for me, is a prime consideration in my choice of which trees to plant. Trees, and the shade they produce, help to keep my home and yard cooler in the summer and warmer in the winter when they act as windbreaks. By providing beauty and character, landscaping with trees also enhances the value of our property.

If you would like to add trees, or even a single tree, to your landscape, be sure to do your homework. There are trees to suit every situation and, by assessing your needs realistically, you can be sure that the tree you invest your money in will return that investment a thousand times over.

First look at the physical aspect of where you want to plant. Choose a tree that, when mature, will be a suitable size for your site. Also, assess things like available sunlight, wind, drainage and soil pH. (You did do a soil test, right?) Do you want an evergreen or a deciduous tree? Do you want spring or summer flowers? Ornamental bark? Berries? Good fall color? Dense shade or filtered shade? A column shape, weeping or rounded form? Small (10-25 ft), medium(25-40 ft.), or large (over 40 ft.)?

There are many trees that offer many combinations of the above so it will be helpful to know what you want before shopping. An experienced nurseryman or landscape/garden designer will be able to help you narrow your choices down, and ultimately buy a tree that is healthy and suited to your needs. And remember, bigger is not always better. The bigger the tree, the longer it will take to become established and put on growth. You may be better off with something smaller that will grow quickly and reach the same height as a larger tree might in the same amount of growing time.

The best time to plant your new tree is during the dormant season - early spring before bud break or in the fall after leaf drop. But trees that have been properly cared for in the nursery or garden center can be planted any time during the growing season. Just know that your tree is going to be more stressed if your plant it in July and you’ll probably have to do some additional watering as well.

And by all means, do your new tree a huge favor by planting it correctly. Many people believe that you need to dig a deep hole when planting a tree. The exact opposite is true. Your hole needs to be much wider than deep by at least three to five times the diameter of the root ball. It needs to be only as deep as the root ball or just 1-2 inches less. It is essential that the root flare (area where the trunk ends and the roots begin) be at or slightly above the existing soil line. Make sure the root flare is visible. The bottom of the hole should be firm so that the tree doesn’t sink after planting.

Remove or cut away twine, burlap (especially the plastic type) and wire baskets. Loosen the roots to enhance their growth and prevent girdling. Finer root systems can be loosened with your hands. Heavier roots may need to be cut with pruning shears. Next position the tree in the hole, making sure that it is straight, and spread out the roots. Backfill the hole with the soil you took out. You don’t need to put in any additives or amendments. Firm the soil gently. Water the tree deeply to begin with, then once a week if it hasn’t rained and more if it’s hot. A good way to judge is when the soil below the mulch is dry, then it’s time to water.

Your final step is to mulch. Add two to four inches around the base of the tree, but not against the trunk. Make a doughnut, not a mound. Mounding mulch around the trunk and covering the root flare inhibits gas exchange and can cause disease and decay of the living bark at the base of the tree. This is one of the biggest mistakes I see in newly planted trees. And I see it everywhere, especially in parking lots around stores and malls. Because of the way these public trees are mulched, many people think that that is how it should be done.

Read other gardening articles by Audrey Hillman