Anyone interested in keeping "Mothers", long term, should get hip to the concept of "Root Trimming"! I'm speaking, strictly, of conventional "soil in pots" gardening.
Root trimming is a technique that is used in Bonsai gardening to control the overall size of the plant - and it's not as complicated as you might think! As Noctern 3 said earlier, I would also suggest using square pots (it's just a lot easier, and less messy, that way!). Whenever the plant becomes "a little rootbound" (not severly), pull it out of the pot, gently, and trim off about an inch, or so, on all four sides and the bottom. After you have killed a couple of plants you will soon begin to realize that removing more than about 25 or 50% of the rootball is not recommended. I have found that "slicing" the rootball with a good, sharp, serrated knife works best (something like a breadknife, to be exact!). Then repot, in the same pot, with additional fresh soil and carry-on!