The bloom of a. rubroviolacea much resembles a. aborescens-- it's red. Hummingbirds will find it. A. ruroviolacea a bit smaller than arborescens (or appears to be). It hasn't been frequently grown. Who knows what it will really do over time in So Cal?
It's an unusual aloe in that it is very cold hardy; the foliage is undamaged at 20 degrees. This is becoming important even along the So Cal coast, as global warming has intensified the climate despite the maritime influence. Here is today"s star::
by Debra Lee Baldwin. http://www.amazon.com/s/ref=nb_ss?url=search-alias%3Dstripbooks&field-keywords=designing+with+succulents&x=19&y=24. The leaves have a subtle red edge,the rest of the leaf a flush of red the eye reads as lavender. This aloe hangs by its toes from cliffs in Yemen in its wild state. Good drainage ---lots of coarse sand in the planting mix---is a good idea.
More about Badlwin's book soon.