Proper Planting Depth Is Key to a Long-Lived Tree!
Trees Are Often Planted Too Deep
If the Tree you’ve planted looks like a telephone pole, it’s going to have problems down the road.
Trees naturally widen at the base of the trunk where the uppermost roots emerge. That swollen part, called the “root flare,” must sit above ground if the Tree is to have a long, healthy life. When planted too deep, with the root flare buried and the trunk straight all the way down (like a telephone pole), the Tree will eventually suffer.
Roots breathe in oxygen and exhale carbon dioxide, like us. Buried under too much soil, roots gasp for air and struggle to perform their normal functions. Oxygen-starved roots frequently grow up instead of out, and in doing so may end up winding around the trunk. These wrap-around roots are known as “girdling roots.” They can strangle the Tree in time.
What Are the Symptoms?
A Tree planted too deeply may appear fine—for a while. Then its growth may slow, it may shed leaves early, it may show some dieback in the canopy. Death may come at 6 months, 1 year, 2 years, or 20 years. It may happen suddenly, as such Trees lack strong buttressing roots, leaving them vulnerable to toppling in strong winds.
How Do Root Flares End Up Too Deep?
Operator error (by the planter) is one reason. The planting hole may be mistakenly dug too deep and the Tree set too low. Sometimes the planter realizes that mistake and throws loose soil in the bottom of the hole to raise the Tree up. When the soil settles, the Tree sinks down and still ends up too low. Please refer to the Bower & Branch™ Tree Planting Guidelines for details on how to get it right.
But planter error isn’t the only reason. Often Trees are potted too deeply at the nursery they came from. Yet another reason that box-store Tree may not be the bargain you thought it was! Bower & Branch™ growers ensure proper potting depths and never allow telephone-pole Trees to leave the nursery.
Another way Trees can end up too deep is when soil is carelessly piled on top of their rootzones and against their trunks, as can happen during construction. A change of grade can be fatal to Trees.
What about Mulch?
A layer of loose, uncompacted mulch is less damaging to root flares than soil, but it is still a bad idea to have mulch right against the trunk. Piling mulch too high and too close to the trunk encourages disease. We call these “mulch vulcanoes.” Pull the mulch away from the trunk and let your Tree breathe.
Can Anything Be Done about Trees Planted Too Deeply?
A skilled arborist can sometimes save a Tree planted too deeply by carefully removing the soil and root mass above the root flare and pruning out any girdling roots.
Clearly, the best solution is to avoid the problem in the first place. Buy Trees from a reputable grower, plant them slightly above grade (we recommend 2 inches), and don’t build mulch vulcanoes. Give your Tree the best start in life you can!