Verdict for Aloe ‘Blue Elf’: not recommended for California’s Central Valley unless protected from frosts
This aloe is a nice compact grower with showy, hummingbird attracting flowers. It needs little if any supplemental water. It has attractive blue-green leaves as its name would imply.
So we figured it was worth a try. We planted it on a mound in full sun where it would have good drainage. The plants were well away from any buildings, so there was no protection from frost. The first frosts damaged the plants slightly. The second burned them pretty badly, and the third froze them right down to nothing.
Sources said the plant was hardy in USDA Zone 9, meaning that it should take frosts down to around 20°F (the zone is “20° – 30°). It seems that 32° F (0° C) is as much as the poor plant can tolerate. Anything below that and it turns to black mush.