To avoid two disadvantages of planting trees



You’ve probably heard the old saying that the best time to plant a tree is 20 years ago, and the second best time is now. If you’ve recently been inspired to add a new tree to your landscape, there are a few steps you can take to get your new acquisition off to a great start.

Trees have very specific preferences regarding planting depth. When a tree grows in an undisturbed natural environment, it is usually able to establish a root system that extends close to the soil surface, providing the growing tree with water, nutrients, and adequate structural support. provides. But often trees are planted too deep in the garden setting, compromising their health and structural integrity.

Trees planted too deeply with root flares below the surface
This commercially grown tree was planted very deeply, with roots well below the soil surface. Some circling roots are also evident. Photo: Adam Glass

Whether the tree is grown in a pot or in a field to be staked at harvest time, the tree’s root flare or buttress flare is usually buried several inches or more below the soil surface. A root flare refers to the lower part of the stem where the first structural roots emerge from the tree. These first structural roots should be at the surface or a few inches below the natural soil level. When the root flare is properly placed, structural roots are able to provide ideal support for the top of the tree, helping it withstand wind and snow loads.

Tree trunks planted at appropriate depth
The trunk of a tree planted at the proper depth is often wider than the base of its trunk. Most of a tree’s root system extends horizontally, collecting water and nutrients from the top few inches of soil. Photo: Adam Glass

Roots also need to undergo respiration and gas exchange to survive. Most of the tree’s root system develops within the top 18 inches of soil, which allows these conversions to occur. Most of the nutrients that a tree needs for proper health are also found near the soil surface. If the roots are buried too deep, the overall health of a tree will be greatly compromised.

To avoid these problems, our first line of defense is to purchase properly grown materials. At the nursery or garden center, inspect potential purchases to the best of your ability without damaging them. This can be done by gently digging at the base of the tree to see if you can feel or see the primary structural roots at the ground level or a few inches below the surface. As a consumer, you have purchasing power that can be used to help shed light on this issue. If the trees are buried too deep, please tell the supplier that this is the reason you will not buy them. But if you’re looking for very specific plant material and don’t have many options, you may need to buy a tree that’s buried too deep and dig up the root flare when planting. do

A tree with a girdling root
Root girdling is essential to maintaining the tree’s long-term health. Photo: Adam Glass

Another common problem with container-grown trees is root girdling or girdling. This happens when a tree is kept too long in its growing container. Developing roots will eventually reach the edges of the container, where they have no choice but to circle the edge of the pot. At the time of planting, these taproots should be either clipped or teased and placed at a 90° angle to the stem. If this does not happen, the roots will continue to grow in a circular direction. Over time, as the trunk diameter increases, it will come into contact with these circular roots, which will eventually occlude or cut off the tree’s vascular system just below the bark layer. This creates a major structural defect, and in some cases causes the tree to die.

If you plant the tree at the proper depth and root around, it should be able to thrive for decades.

-Adam Glass is a garden curator and rosarian at the Scott Arboretum at Swarthmore College in Swarthmore, Pennsylvania.

New to planting trees? Check out this article from our Gardening Basics Project Guide: Planting Trees and Shrubs The Right Way

For extreme cases of root rot, you may need to try more extreme techniques. Here’s where to start: A better solution for root-bound plants



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