American wisteria (Wisteria frutescens) beautifully covers a pergola in the Garden with its showy, fragrant blooms. Native to the eastern United States, it grows best in full sun in zones 5-9. The woody vine can grow up to 20-30 feet. American wisteria is not as aggressive in spreading as Chinese wisteria (Wisteria sinensis). It attracts butterflies and is a larval host for Marine Blue, Zarucco Duskywing, and skippers. | U.S. Botanic Garden