The Blue Chalk senecio is pretty hardy for me in z9b. I've never lost any due to frost. We usually dip to the low 30s with an ocassional night or two in the high 20s. It's easier to lose them to overwatering in the summer months.

I've never grown the himalaya variety, but it looks like a variety of Sencio cylindricus, and that one is more sensitive to frost. I've lost it to frost even in protected spots in the yard.

Good luck!

Thank you so much for sharing your experience. I will bring the Himalayan to the covered porch area and protect when n temps are to hit 32 deg. Neither of these plants are very large so I can move the containers to a protected area.
Molly