A TREE PLANTED TOO DEEP CAN BE DETRIMENTAL ITS HEALTH
HOW DOES IT HAPPEN?
It is one of the most common problems we find with nursery trees that have been planted in commercial and residential settings. In a 1991 survey, 93% of professionally planted trees had root collars obscured by soil or mulch (Smiley and Booth, 2000). In another survey conducted by the University of Rhode Island's Sustainable Landscape Arboretum, buried root collars were present in over 75% of the nursery-grown trees examined, and the depth of burial ranged from 3 to 12 inches (Maynard 1995).
The process begins with a tree seed or cutting that is sown in a medium in some form of container. As the roots of that tree begin to outgrow the container, the tree is potted into a bigger container, each time adding more medium to fill the larger pot. More times than not, the top of the natural flare of the tree or plant is covered with more and more medium. By the time the tree is ready for sale to the customer, the natural root flare could be inches or even sometimes feet below the top of the medium line in its existing pot. Another problem that can occur from container trees is circling roots within the pot due to the tree not being moved into a larger container quick enough. These roots will be trained to continue circling, even when they are planted in the ground. Addressing these issues prior to placing a tree in the ground is critical to future success of the tree.
Continuing on the process, the customer then buys the tree and either plants it themselves or has the nursery plant the tree in their yard. Unbeknownst to the customer or the crews planting the tree, the tree's natural root flare is planted below the grade of the yard in which it is planted. This causes the existing root system to be too low and can sometimes starve the roots of needed oxygen. Additionally, the soil or medium that is contacting the trunk of the tree will activate adventitious buds within the contact area and sprout new roots (adventitious roots) that will attempt to root into a higher soil line where oxygen is more prevalent. Someone might say that more roots are better but in this case, they would be mistaken. The adventitious roots begin growing above the buttress roots (where the natural flare is) and over time, begin to cut into or girdle the buttress roots where a large portion of the water intake and nutrients are potentially flowing (if not killed by oxygen starvation or rot) into the tree via smaller roots (feeder roots) attached to the buttress roots.
To make matters even worse, landscape crews and sometimes homeowners will pile large amounts of mulch around the newly planted tree, sometimes forming what is called a "mulch volcano". This has the exact same effect as if planting the tree too deep into the soil. Mulch acts the same as soil, harboring moisture and a medium for adventitious roots to activate and begin growing. Not only that, the mulch is also a prime area for anaerobic conditions and bugs to set up shop if piled too high. These problems only accelerate the decline of an already stressed tree. Don't get me wrong, mulching a newly planted tree is highly recommended and we do it for every tree we plant. When not done properly, it can be one more added stressor to a tree.
Links to studies in this area of research: C Wells 2006 ; RJ Hauer 2021 ; EF Gilman 2010
IS THE ROOT FLARE PART OF THE ROOTS OR THE TRUNK?
Next time you are on a walk in the woods try to locate some trees that have naturally sprouted (not planted) from a seed. Unless they are in an area where water may have shifted the soil or there has been some construction, you should see a well defined flare at the bottom of the tree. This is because the seed came to rest on top or just underneath the soil. From that point forward in its growth, no soil was added, only organic matter such as fallen leaves or pine needles, just as God intended. A good rule of thumb, if your tree looks like a telephone or utility pole in your yard, it is too deep.
In talking with customers, many have said when seeing a well defined root flare that "I thought that was the roots so I covered it with dirt to protect them". It is a very common response. I believe that improper planting has been going on for so long that we have become accustomed to thinking the "telephone pole" look or the "mulch volcano" are standard practices. Why wouldn't we think that? We see professional landscapers doing it every day. It isn't difficult finding these improper plantings all over your city and residential landscapes. Next time you are driving around town see how many you can spot. It is everywhere.
So why is it this so important? The answer to that question is because of the answer of the original question that was posed at the beginning of this section, "is the root flare a part of the roots or the trunk?" The root flare, ironically, is a part of the trunk of the tree. The root flare has bark much like the trunk of the tree. Exposing this area to continuous moisture caused by soil or mulch can cause this area to rot, killing cambium tissue and/or sprouting adventitious roots that can grow into the trunk of the tree, cutting off the flow of nutrients and water. Rotting tree parts and stressed trees also attract bugs that now have direct access to the tree via the rotting wounds and now serve as a secondary stressor.
Keeping the root flare exposed where the bark is allowed to dry and be exposed to oxygen is crucial to the overall health and vigor of all trees.
CAN MY TREE BE SAVED?
I would like to say that every tree that is experiencing the stress of being planted too deeply and/or being choked by circling or girdling roots is salvageable, but unfortunately this is not always the case. We at Natural Texas take great pride in making sure that our customers are given all of the information, even if it means bad news.
With that said, we have been successful in saving a lot of trees from these ailments and we are very eager to come look at your trees to give you an honest assessment. The only way we can get the fullest picture is to remove the soil using mechanical or pneumatic (AirSpade) means to see what is happening underneath the soil. Once we are able to look at the root system we will work with you on coming up with a treatment plan to address the issues. This can sometimes include root pruning of girdling roots, aeration, fungicide treatment, fertilization, etc..
In extreme cases where the health of the tree has deteriorated too much or the amount of girdling roots would be too much to remove, putting the tree at risk of structural failure or too much root loss, a recommendation for removal will be made. The key is to identify these issues prior to excessive symptoms and address them as quick as possible.
Our goal in all this information is to help you spot the problems or potential to have problems before your valuable trees start to decline.
Give us a call and let us know what we can do to help.
