The iconic Monarch butterfly is declining. They need milkweed for their survival and the best perennial species for Regina is swamp milkweed (asclepias incarnata). It grows to a height of 3-4' in full sun to partial shade. It's not invasive; plant 2-3' apart and keep soil fairly moist. Also attracts other pollinators. Fall is a fine time to plant perennials. If interested, contact me and I will pot up for you.