Benny,

I think that crosses with brevifolia would be fertile on other Yucca, too bad that there aren't any reports of anyone trying them! Like I said I missed the blooming season last time I was in the habitat (2012).

Not sure what I have that will bloom this year, hopefully glauca and one of the hybrids (most with filamentosa). The Yucca moths here leave the glauca alone but are nearly impossible to get off the filamentosa or hybrids thereof. I also have a seed grown 'elata' that bloomed last year, however it is almost certainly not an 'elata', but probaby a Yucca glauca v. stricta. If it blooms again I will also try to hybridize onto it.