These adaptable plants are indigenous to North and Central America and the West Indies. They are grown for their decorative, sword-like leaves that vary in rosette form, leaf width, shades of green or blue, and variegation. They produce very large spikes of hanging bell-shaped flowers that are most often white. They are ideal for containers, desert gardens, gravel gardens, or rock gardens, where their silouettes stand out; also grow in mixed borders, where their forms contrast against a softer backdrop. Some of the tender species form massive specimens.