Deciduous trees are prone to suckers, which means (as our photo above shows) that your tree has put forth the effort to produce a new branch or stem, but it's near the base of the tree and is not needed there. Suckers happen on most deciduous trees, especially Crape Myrtles, Dogwoods, Japanese Maples, and younger trees in general. Prune those low-growing stems or branches as soon as you notice them (if you don't want them there, of course) because they "suck" the energy that your tree could be used to instead put out more height where it needs it.
The same goes with any low-growing branches that you don't want- prune them. The sooner you do, the sooner the tree will put its energy into other parts of the tree. You may have to do this a few times during the growing season. Some trees, such as Crape Myrtles, will put out several stems and branches further down the trunk than you might want. A simple, quick prune is all that's needed to help your tree grow taller this spring and summer.