With the fall season upon us, tree planting season will be in full swing. Tree planting may seem like an easy task for a so-called landscape “professional” to perform. However, the majority of newly planted trees that I either see or consult on are planted incorrectly. Wait, there’s a wrong way to plant a tree? Believe it or not, there is.
In the tree care and tree production industries we have standards which we are supposed to utilize. For tree planting, the standard is ANSI A300 Part 6: Planting and Transplanting (R2018). As practitioners, these standards provide the do’s and don’ts of tree planting. However, for the standards to apply the business completing the tree planting must specify the applicable standard in the contractual agreement with the client. If there is no reference that the trees will be planted in accordance with ANSI A300 Part 6: Planting and Transplanting (R2018) then there is no recourse for the client, should the tree be planted incorrectly according to standard. You’ll be pleased to know that Oak Bros Tree Care does reference ANSI A300 Part 6 in all of our tree planting contracts with clients to protect both the client and the business. As a client having a tree planted, this is reassurance that the tree is being planted with longevity in mind.
Now that all of the boring stuff is out of the way, let’s talk about the most important part of planting a tree: planting depth. This is meant to be a primer article with just the basics that every homeowner should understand.
Trees are an investment in the future and should be treated as such at installation. That’s not always the case, however. I spend a lot of time in the field consulting on young and old trees which were planted incorrectly and, as a result, have a reduced lifespan. The most common tree planting issue is that trees are planted too deep on the client’s site. By “too deep” I mean that the trunk flare (transition between trunk and 1st order roots) is below the existing grade, when it should be at or slightly above grade. This causes compression of the stem and a lack of structural root development over time. Ultimately, this leads to a tree with a lower lifespan than anticipated. How low? It depends. In some cases, we see trees decline within a few years after planting. In other cases we see it happen decades later after being triggered by another stressor such as drought injury.
6” of soil removed to find trunk flare
In the photo above, I removed 6” of soil from around the trunk before I found the highest trunk flare. Had the soil not been excavated to expose the trunk flare, this tree would grow very little and have a lower lifespan.
Newly installed tree planted too high
In the case of the Spruce above, the hole was dug too shallow and the burlap was left on the root ball. While the burlap should be removed from the root ball, it’s not mandatory per the planting standards. The issue with leaving burlap on the root ball is that it reduces root spread into parent soil and causes water to deflect outside of the root ball, leading to water stress and decline.
Planting a tree at the correct depth is an incredibly simple process so long as the steps are completed in the correct order.
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Before planting, find the trunk flare in the root ball and remove any excess soil. If you don’t, there's a very high likelihood that you will plant the tree too deep.
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Dig the planting hole to the depth of the distance between your highest trunk flare to the bottom of the root ball.
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Burlap and wire should be removed in the upper 25% of the root ball.
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That’s it. It’s not complicated, but those 3 steps are commonly forgotten and newly planted trees suffer during their short lifespan.
4” of soil was removed from the root ball to expose the trunk flare prior to digging the planting hole.
Board Certified Master Arborist
Plant Healthcare Specialist
Aaron Shulz
