... the state flower of New Mexico, and I, at least, would call this, yucca elata, "soapweed yucca." Only my trusty new wildflower book thinks that "soapweed yucca" is the smaller yucca intermedia. Nonetheless ... these grow very tall - indeed, one the other side of this driveway - a far larger clump than these - has collapsed and bent over completely. "Soapweed," because Native tribes not only have used the leaves for baskets and sandals and so on (and the Apache used the fibers for dental floss) but the white substance inside the trunk and roots was commonly used as shampoo - it's supposed to be good against dandruff and hair loss. The Zuni used to mix it with ground aster and used it as a soap to stimulate hair growth on the scalp of new borns. Even not knowing about if efficaciousness, it's very striking.