This vegetative selection of A. americana var. protamericana makes the largest clump of any of the hardy agaves that we have grown. Instead of forming a tight, upright clump as is typical with "protamericana," A. 'Big Blue' makes a more open clump resembling A. americana, reaching 3' tall x 10' wide. We usually see a little leaf burn when temperatures drop much below 10 degrees F, which is still far hardier than typical Agave americana. In loose soils, this selection forms offsets up to 6' away from the main clump...very stunning. The original clump was grown from seed from a Yucca Do collection between Saltillo and Monterrey, Mexico.