Yucca Tree

Carlsbad, NM ---- On a trip back home in March 2013 we stopped at the Living Desert Zoo and Botanical Gardens State Park in Carlsbad (known for its caverns, which we didn't see). The gardens offered some types of plants that we don't see in Northern New Mexico. I've tried to research this tree and the best I can do is a Soaptree Yucca, but in many ways it looks like a Joshua Tree.