hey charles, hesperaloe parviflora has done well for me here on border of zone 7B/8A in georgia. i do think they like plenty of heat. they are fairly slow-growing, but on the other hand.....their blooms last for weeks when they flower. i suggest them for trial! y. rostrata does well here for me, also y. thompsoniana. have not grown sapphire skies. never heard of the cultivar rosemary. good luck! randy