Unfortunately, the majority of trees I see planted look like this.
Notice the roof flare is not visible on the above tree. Not good! This tree will struggle throughout it’s life. By my estimation, the root flare of this tree is buried under at least 4-6″ of mulch and soil, maybe more. This is a common occurrence after a lot of landscapers and homeowners plant trees. It’s an epidemic that has plagued our industry for years. Part of the problem is homeowners and professional landscapers alike, don’t know any better despite much effort from trade organizations, academia and certain media groups. Another problem is that most balled and burlap plants come directly from the nurseries already buried under too much soil. The reason for this is due to a couple factors. For one, when nurseries line out their fields, they line out whips. Whips are very immature trees that are planted bare root or without soil. Without a soil mass and typically a very small root system, trees are hard to keep upright. Because of this, trees are planted deeper than they should be so they stand upright until the workers can get back to them for staking. Reason two is due to the way nurseries maintain their fields. Labor is expensive so many tasks are done mechanically including weeding. Machines disturb areas between rows and that soil is inevitable spread to the edges of each row, adding even more soil to an already buried tree.
When planting a tree, the root flare should end up just above the surrounding grade. Sometimes the root flare is buried, sometimes it isn’t. Before you decide how deep you need to dig the hole for a tree, you need to locate the root flare. The root flare will be the determining factor when deciding what height the tree should be located in the soil profile.
As an experiment, go for a walk into the woods. Look at the base of trees. You’ll see a root flare in every instance. Now go for a walk around a built landscape. In most cases, the base of trees look very different, more like the second picture above. Why should you care about the plant height and root flare? Well, a tree that is planted too deep will struggle throughout it’s life compared to a similar tree planted correctly. Will it die? Maybe, maybe not. Will the tree grow more slowly? Yes. Will the leaves be smaller and the canopy of the tree not as full? Yes. Will there be a potential for more insect and diseases throughout it’s life? It is highly likely.
Plant height is the first step towards a healthy long lived tree.
In the example above, this girdle was not visible when we purchased this tree. The girdle was right at the soil line. When we plant a tree, we always look for and expose the root flare. We dig to find it removing all consequential roots along the way. This tree came directly from the nursery with 8″ of soil above the root flare. If we planted it as is, where the top of the root ball was at the surrounding grade, this tree would have struggled through life. It would have been too deep considering it arrived with so much soil above the root flare even without finding the string that girdled the stem. Rather than return the tree, we removed it from the clients yard and planted it at my house. This tree appears to be a beautiful, healthy specimen. In reality, it worthless. I planted it at my house because I’m curious if this tree survives long term. Will the girdle correct itself as tree caliper increases or if that girdle with create a week spot that will break at some point.
Removing as much of the wire basket as possible and positioning the tree so the root flare is at existing grade are important factors when planting a tree that will last and thrive for decades.