Asclepias incarnata (Swamp Milkweed) is a wildflower with very beautiful clusters of pink flowers in summer and is a favorite larval food for Monarch butterflies. It grows in medium to moist soil conditions (it doesn't need a swamp) and many types of soil including clay. A great species for rain gardens. USDA zones 3-8. Seeds require special prep for germination. See our planting guide below. Asclepias incarnata native range: AL, AR, CO, CT, DC, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, PA, RI, SC, SD, TN, TX, UT, VA, VT, WI, WV, WY.