Hi Laura, I’m not accustomed to expanding in Idaho, but we do are in the same USDA hardiness zone. Two kinds of milkweed that catch the attention of lots of monarch action are swamp milkweed (asclepias incarnata) and tropical milkweed (asclepias curassavica) since they are used as both of those http://cannabis21086.jaiblogs.com/12511785/not-known-facts-about-antelope-weed-seeds