Some yellowing of the lower leaves is expected with transplant, especially at this time of year. Yuccas native to the Southeastern US, such as Adam's needle, are more water tolerant. Most western yuccas don't need water more than 3 X /month in the warmest months, and not at all after mid october in Albuquerque, Nov 1 in southern NM. If you move them frequently, though, they won't be very disease resistant. Oleanders need a lot of water when first planted, as long as in well drained soil. Good luck. dl

My Yucca Baccata's leaves also turned a purpleish shade. I think that it was adapting to the new lighting conditions. It eventually went away though...