The ponytail palm takes its name from its resemblance to hair
cascadeing out of a ponytail. It's also called a "bottle palm" because
its trunk becomes a bottle like bulb at soil level. Because of its
massive size the plants are mostly root-bound. While they can store
water in their bulb, and use their water slowly, they probably don't
have a lot of soil in their pot. If the roots become too dry the lower
leaves turn brown or yellow and the plant looks a little ashy.