I was browsing online about hardy cacti and succulents and came across some hardy agaves I'd like to try growing. I was wondering if A. parryi and A. havardiana would survive the winters in my area. The soil they will be growing in is regular topsoil mixed with crushed limestone. I already have a couple types of hardy prickly pear as well as a couple types of hardy yucca growing and was thinking about expanding my small collection of cold hardy cacti/succulents. Any information on winter protection or growing techniques is more than welcome. I was considering laying some of that thick black plastic over the top of the plants from late fall through spring (our wettest time of year) to keep out the water as well as help insulate the plants during the winter. I was also thinking about the possibility of building a small cold frame for these guys out of some old windows I have laying around. Thanks all for advice/input!