An important plant that is typically found in moist soil, often near the shore of ponds lakes and streams in this area is swamp milkweed or Asclepias incarnata. This native perennial is one of the primary food sources for the monarch butterfly caterpillar. The sap of the milkweed family is toxic and can cause irritation, sickness and death in animals that digest too much of the plant. This poison does not seem to effect the monarch though, in fact it is beneficial to the monarchs who themselves become toxic from ingesting the milkweed. This often prevents many predators from eating monarchs more then one time, that is if they survive the first time. The flower of swamp milkweed can be quite beautiful and often attracts adult monarchs and bees looking for nectar and pollen. I photographed this flowering milkweed along the St Croix River in Wild River State Park last summer.