Milkweed is the sole food source for monarch butterfly caterpillars and is also attractive to other butterflies, bees, and humminbirds.  Showy milkweed is a Saskatchewan native perennial.  Plants are shorter and more drought-tolerant than some other varieties of milkweed.  Plants will self sow and can spread by rhizomes and can take over garden areas - grow in contained areas and/or remove seed pods to reduce unwanted spread of plants.  Perennial, hardy to zone 3.