What’s the longest flowering perennial?
These reliable plants keep going for months, providing continuous colour from early summer into autumn with very little care. Some of the best include geranium rozanne, famous for its incredibly long flowering season, and salvia caradonna, which blooms early and often. Some of the best include geranium rozanne, famous for its incredibly long flowering season, and salvia caradonna, which blooms early and often. Gaura whirling butterflies, verbena bonariensis, scabiosa butterfly blue and nepeta six hills giant also flower for much of the summer.Geranium. Probably one of the longest flowering garden plants, hardy geraniums start flowering around may, and continue to october, depending on the variety. One of the longest flowering varieties is geranium ‘johnson’s blue’ (illustrated) which is also attractive to bees.