Actually, "Ballooning" has nothing to do with landing - it is just often observed during landings

As several people said, it has everything to do with a high-lift wing traveling faster than it needs to.

One of the best examples is when turning a trainer: If the nose is allowed to drop during the turn, the plane will pick up speed. Then, once the wings are leveled, the wing will translate that speed into lift, and so the plane will balloon as soon as the wings are level.