This is an unusual tuberous-rooted perennial plant that I grew from seed many years ago. It is a herbaceous plant, dying to the ground in winter and re-emerging each spring. It has rather succulent-looking, shiny leaves, which in the form I grow, are of a brilliant lime-green/gold hue. It grows to about 60 cm in height. It has very thin spires of tiny pink flowers in late spring and summer - I usually cut these off as they clash with the leaves and if left on, the plant will develop into seeds that will germinate with frightening efficency. Its native habitat is from Southern USA to Central America. I find it grows in sun or shade and in any sort of soil. It seems to be quite drought hardy. It provides a great contrast to plain green foliage and is best grown in groups to provide a mass. I have seen a picture of a cultivar named 'Variegatum' with white-variegated leaves, which looked good.
Beware that this plant self-seeds prodigiously! I pull out 99% of the seedlings I find in my garden.