When it comes to fall foliage colors, we usually think first of trees and shrubs. From the flaming reds, yellows, and oranges of maples to the rich red of chokeberry and the bright yellow of the ginkgo tree, many woody plants put on an eye-catching seasonal show as the weather cools.
But for some excellent fall leaf color on the floor of the garden, as well as attractive flowers earlier in the season, along with easy care, consider some of the hardy geraniums. Also known as cranesbills for the shape of their seedpods, these Geranium species are not related to the bright Pelargoniums that, confusingly, are commonly called geraniums.
From among the many choices of hardy geraniums available, a multi-year evaluation of a wide range species and cultivars carried out at the Chicago Botanic Garden, located in zone 5b, can help you choose the best for continued seasonal interest. Over 100 Geranium species and cultivars were assessed for their ornamental traits, resistance to pests and disease, cultural adaptability, and winter hardiness, and given a rating of one to four stars.
Among the hardy geraniums that received a rating of three or four stars, many display colorful leaves in autumn. 'Brookside', with deep blue flowers in late spring to midsummer, takes on hues of red and burgundy. The prolifically blooming Rozanne (G.'Gerwat') is covered with purple-blue blossoms all summer long, and its leaves make a tapestry of red, orange, and yellow in fall. The bigroot geranium cultivars 'Lohfelden' and 'Minor' were top-rated, but all varieties of this species are good choices for late season leaf color. Purple flowering G. wlassovianum (pictured) and pink or white flowered G. x cantabrigiense and its cultivars are also tops for fall color, turning shades of red and purple.