What is the longest blooming flowering shrub?
Butterfly bush have one of the longest bloom times of all garden plants: they seem to never be without flowers from early summer through autumn. This makes them perhaps better called “continuous bloomers” or continuous blooming shrubs over rebloomers, and excellent shrubs that bloom all 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.