The Dracaena species known as snake plants or mother-in-law's tongue were until recently considered a separate genus, Sansevieria, but have been reclassified following molecular examination.

Mother-in-law's tongue does indeed prefer to remain in the same pot, undisturbed, for as long as possible, though we would usually advise replacing some of the top layer of soil each year. They really like to be root-bound and can remain in the pot even when the roots come up above the top of the soil. Once the plant is close to bursting its pot or the leaves cover the entire surface of the soil, it is time for a change.

The right time to repot your plant is in the spring when it is entering a growing phase and will recover the most quickly from the transfer. Select a new pot with a drain hole in the bottom. Terracotta pots are good for these plants because they are heavy enough to balance the tall plant. Pack the bottom of the pot with some broken pot shards to help keep the soil draining freely. The proper, quick-draining, soil is essential. Potting soil plus one third sand or perlite and up to one third peat added works well.

Be as gentle as possible removing your plant from the current container. If you water ahead of time, the soil will be soft and easier to release from the pot. If it is firmly stuck, it may be necessary to break the old pot. The roots are relatively small and shallow for this plant. Handle them gently and dust the old soil from the roots as well as you can before repotting.

Courtesy of NYBG Plant Information