For springtime romance, few plants compare to wisteria. This woody vine happily climbs and clambers over trellis or pergola, delivering a spring show of dangling flower clusters packed with fragrance. Different types of wisteria are available with flowers in shades of purple, pink, blue and white. Choose American wisteria for plants that aren’t invasive, especially in warmest zones. Hardy in Zones 4-9, depending on type.