Ask Mr. Smarty Plants

Mr. Smarty Plants is not the "see-all, knows-all, tells-all" expert on all things plants but we do try to find expert information to pass on to our readers. We are, in short, conduits of information, not sources. Apparently you have already been following our answers on live oak suckers/sprouts/words we don't repeat, so you know our basic response to these questions, but will add a link to previous answers for others. We can't verify the answer you heard about. When we tried, again, by searching the Internet, we got a lot of forums, which feature personal experience or opinion by other gardeners, and often find ourselves there, too. So, rather than go to a forum for personal experience, please consider our theory on this very common problem.

We understand the area of the tree you are referring to; one of our frequently used answers to why a tree puts up suckers is that the tree has been damaged in some way, and the suckers are auxiliary locations for leaves, which manufacture food for the main plant. There is a very good possiblity that dirt too high on the base of the tree can be damaging to that tree. We always recommend that dirt or mulch not be piled up against a tree trunk as it can lead to insects or fungi moving in on the tree. If we had a live oak with that kind of "dirt pile," we would remove it just for the health of the tree. Whether or not that would reduce the production of suckers we simply don't know.

Notice in the illustrations we have provided below that there are several trees growing together, in the wild. These represent a motte, a common way that live oaks grow in the wild. The suckers that come up and survive grow into smaller trees. Often there are very large mottes, which are attractive from a distance but too much for a residential location, and sometimes lead to the spread of Oak Wilt via the proximity of roots from other, infected, roots.

Killing oak sprouts