Sorry to yell, but we have been running into a lot of trees lately that were planted too deep! Most of these trees were installed by very “reputable” nurseries and landscapers – don’t their people know how to plant a tree properly?
The root crown of a tree (the place along the trunk where the roots come out) is supposed to be RIGHT AT GROUND LEVEL! (This might not be the ground level in the container if the nursery didn’t know what they were doing!) If the tree is planted too deep, with soil continually against the trunk, chances are that the tree will not flourish and will die prematurely. A trees trunk tissue was made to be in the air. A trees roots were made to be in the ground. That isn’t too technical is it? (Just a note, a trees roots will only grow where there is both water and oxygen) Tree roots rising out of the ground are not a problem for the tree, although they may be a pain to mow over if you have grass. When trunk tissue is in contact with the soil, it causes stress to the tree and the tissue is subject to fungal attack.
Even a few inches can make a difference, how about this:
A tree we replaced because it wasn't doing well - quess why?
You can see from my Leatherman Wave (which is 4″ long) that this tree was planted 13-14″ too deep! It had been in the ground for 3 years and had not grown much at all. The root system was not bad, and the tree would likely have been fine if it had been planted correctly. We replaced this tree with a great “Desert Museum” Palo Verde from Arid Zone Trees (see this article).
There are only a few options in dealing with a tree that has been planted too deeply – either take it out, or excavate around the trunk to expose the root crown to the air. When we excavate around the trunk we need to be REALLY careful not to damage the bark. We need to remove the soil out several feet from the trunk and leave a saucer-shaped depression. Sometimes we also find problems with girdling roots during this excavation. It is not a cure for the problem, but hopefully enough of a benefit that the tree can survive (especially if it is an established tree that has been installed for a period of time). If the saucers are more than a few inches deep they tend to fill in with leaf litter & mulch, and also hold water which is not desirable, but since raising the tree is impossible, it is about the only thing we can do.
We are seeing trees planted 15-20 years ago that are dying because of this problem. At that point, excavation probably won’t help, so an expensive removal and replacement is probably the only option. I really wish the nurseries and landscapers wouldn’t plant trees too deep!
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