Here in SC PA, Blue Flag Iris (Iris versicolor) is only native in York and Dauphin counties. In these counties it supports 13 caterpillar species. It is native throughout the Northeastern US and Canada.
Blue flag iris is found growing in marshes, wet meadows, and other wetland areas. Plant it in that continually damp spot or on the edge of a pond or stream. It blooms with bluish-purple flowers in late spring. Wear gloves when handling the rhizomes as they are poisonous. Sources: USDA, Missouri Botanical Garden, "Native Herbaceus Plants of South Central Pennsylvania" by Cumberland County Master Gardener Susan Skender 📷: NatureFriend on Pixabay