Hardy geraniums are easy to grow. Most species prefer moist, well-drained soils and partial shade to full sun. They have few insect or disease problems.
In spite of their favorable qualities, hardy geraniums are not widely planted in home gardens. Gardeners may want to try some of the following species and cultivars.
Geranium x cantabrigiense 'Biokovo' is a hybrid discovered by the German plantsman, Dr. Hans Simon, in the Biokovo Mountains in the former Yugoslavia. 'Biokovo' forms 6-inch-tall mound. Its aromatic foliage turns a striking red in the fall. In late spring and early summer, plants produce numerous white flowers tinged with pink.
G. x cantabrigiense 'Karmina' is a low, clump forming cultivar which produces dark pink flowers in early summer. The fragrant foliage turns red in the fall.
G. endressii 'Wargrave Pink' forms mound-shaped plants that produce clear pink flowers during the summer months. Foliage is a light green.
G. himalayense 'Plenum' is also sold under the cultivar name 'Birch Double.' 'Plenum' produces double, pale purple-violet flowers atop 1-foot-tall plants. Plants possess a sprawling habit. Its foliage is an attractive orange-red in the fall.
Geranium x 'Johnson's Blue' is thought to be a hybrid of G. pratense and G. himalayense. Plants grow 15 to 18 inches tall and have a somewhat sprawling habit. The flowers are a clear blue. 'Johnson's Blue' blooms from June to September.
The bloodred geranium (Geranium sanguineum) and several of its cultivars are excellent plants for the home garden. G. sanguineum is a clump-forming plant which grows 6 to 12 inches tall and spreads 2 feet wide. The species produces magenta-colored flowers. The foliage turns red to maroon in the fall. The bloodred geranium is easy to grow. It tolerates both hot and dry conditions.
G. sanguineum var. striatum is the most widely planted cultivar. It is also sold as 'Lancastriense' or 'Prostratum.' Plants are 6 to 8 inches tall and produce light pink flowers with crimson veins. The cultivar blooms heavily in late May to early June, then intermittently through the summer.
G. sanguineum 'Alpenglow' forms a 1-foot-tall mound. The dark green foliage turns deep red in the fall. 'Alpenglow' blooms heavily in early summer and sporadically until frost. The variety originated at Alpenglow Gardens in British Columbia.
'Album' is another fine cultivar of bloodred geranium. 'Album' grows 10 to 12 inches tall and produces pure white flowers.
All of the aforementioned geraniums are hardy throughout Iowa.
Hardy geraniums should not be confused with the common garden geraniums. Garden geraniums are not true geraniums. Garden geraniums are annual plants which belong to the genus Pelargonium.
This article originally appeared in the May 9, 1997 issue, pp. 62-63.