Dieffenbachia is a genus of tropical plants in the Family Araceae noted for their patterned leaves. Members of this genus are popular as houseplants. Water thoroughly, then let soil dry to the touch to a depth of one inch. Dieffenbachias will grow well in most well-drained container soil mixes. If the stems become too long and bare, you can rejuvenate the plant simply by cutting the stems back to about 6 inches tall.