This is a question we get asked a lot. They don’t. It is a myth that persists.
The reason that it persists is because corns do often keep coming back after we have removed them. They do not come back because we left the “root” there, like the plant analogy that the myth is based on. They come back because the cause of the corn is still there. They only way to stop a corn coming back is to remove that cause. Just removing a corn does not remove that cause.
A skilled podiatrist can easily remove a corn, but as that corn is caused by too much pressure on the area in which it develops, unless that pressure is removed the corn will return. You need to discus it with your podiatrist what needs to be done to either eliminate that excessive pressure or reduce it so that the corn is not so much of a problem.
The reason for that high pressure will vary from “corn to corn”, but it could be from, for example, a hammer toe pushing on tight fitting shoes; it could be between the toes and the alignment of the toes is off slightly, causing high pressure on the spot where the corn develops; or it could be from the shoe pushing on a bunion. The reason for the corn needs to be determined and that reason taken away if the corn is to be stopped from returning.
How that pressure is removed is going to be determined by the reason for the pressure. Was it the shape of the toe? Is there a bit of enlarged bone? Do the shoes not fit properly? Once that has been assessed then advice can be given on the best strategy to remove or lesson that pressure to prevent them from coming back
Bottom line is that corns do not have roots.