Milkweed is the common name for Asclepias. And yes....monarchs love it. There are several types of Asclepias (milkweed) readily available at garden centers. Perhaps the easiest to find is Asclepias tuberosa, also known as butterfly weed. There is also Asclepias incarnata and Asclepias verticilata. If you can't find it now, you sure can in the spring. I do know the UD Botanic Gardens will have it at their spring sale.