The great uniformity in the flowers of yuccas can be explained by their pollination. This relationship is exclusive - the moths depend on developing yucca pods as food for their larvae, and , in the process of laying eggs, they very deliberately pollinate the flowers. Joshua trees are very difficult to grow outside of their native habitat, but other arborescent species can be grown in mild areas. Like agaves, this latter species dies after blooming. Yuccas prefer well-drained soil and full sun, but, with the exception of the Joshua tree, they are not fussy.
All species are tolerant of at least light frost, and some are very hardy.
The Ruth Bancroft Garden.