Ask Mr. Smarty Plants

You didn't find it in the databases as it is a brand new species - Quite rare.  Isn't that a great find!  They put it right next to the Mr Smarty Plants table and I was VERY tempted.

New to Science reports that Yucca cernua was discovered by Eric Keith in East Texas in 2003.  Their record says that it apparently is restricted to brownish, acidic clayey soils of the Redco Soil Series in Jasper and Newton counties.  However in Daves Garden, Eric Keith (coincidence?) reports that  "In its natural habitat, the plants grow in an unusual acidic clay in the Redco Soil Series. However, I have grown several plants from seed and they seem to thrive in low pH sand and high pH black clay. They do well in disturbed areas such as roadside and other ROW in the wild as well."

Bennys Cactus speculated that the status of Yucca cernua is uncertain; it might be a natural hybrid with genes from Yucca rupicola (Twistleaf yucca) or Yucca pallida (Pale-leaf yucca).  Several other web references had similar guesses towards closely related Yucca's, generally at least including those two.   I would consider it a good guess that the growing conditions for Yucca cernua would be similar.  Happily, other than the soil, the recommended growing conditions for both are the same.   That would be:

Water Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry
Cold Tolerant: yes

Hope this helps!   As a parting comment - I hope you put your name/email on the list of people that purchased the plant.  I believe the Wildflower Center wants to track how well they do as people try to grow them; that will provide information to the next generation of Yucca cernua owners.