Geranium is a genus in the Geraniaceae family of around 400 species found in temperate regions. The name Geranium means "crane" in Greek, and the common English name of many species is "crane's bill" although this may be a reference to the distinctive seed capsules. Geraniums should not be confused with the plants the horticultural trade refers to as "Geraniums", which are species of Pelargonium. Geranium species have 10 fertile stamens. Pelargonium species also have 10 stamens, but they are not all fertile. Only 1,2,3,4,5, or 7 are fertile.
Geranium maculatum L. is known as 'Wild Geranium' and is native to the East of North America. The high tannin content of its rhizome led early settlers to use it for tanning hide. Extracts from the rhizome are also used as herbal medicines.
Geranium × magnificum is a hybrid of Geranium ibericum Cav. and Geranium platypetalum Fisch. & C.A.Mey. A typical vigorous cottage garden blue geranium easily passed along by digging up a chunk of rhizome. Photographs by David Pilling.
Geranium × oxonianum is a hybrid of Geranium endressii J.Gay and Geranium versicolor L. There are many named cultivars and the vigorous plants are common cottage garden hardy geraniums. The typical height is 18 inches and spreading rhizomes mean the plants form large clumps. New plants can easily be propagated from pieces of rhizome. Photographs by David Pilling show characteristic Geranium palmate leaves, rhizome and seed production (black spot at the base of the 'bill').
Geranium richardsonii Fisch. & Trautv. is commonly known as Richardson's geranium. It is native to western North America from Alaska to New Mexico, where it can be found in a number of habitats, especially open aspen and spruce forests. Leaves are bright green and flowers are borne on stalks up to 12 cm (6"). The leaves of the wild white geranium are edible and can be added to soups and salads. Hardy to Zone 2, possibly colder. Photos contributed by Paige Woodward.
Geranium transversale (Kar. & Kir.) Vved. ex Pavlov 'Rose Foundling' is now considered by Plants of the World online to be a synonym of Geranium linearilobum subsp. transversale (Kar. & Kir.) P.H.Davis which is a synonym of Geranium linearilobum DC. This is a unique, bright, deep pink form of the normally pallid tuberous species native to Central Asia, W Siberia and N China and originally found in the Aktash mountains in Uzbekistan. Photos contributed by Paige Woodward.
Geranium tuberosum L. is a tuberous species that originates from southern Europe into Asia Minor. It is dormant in summer. It has small pink/blue flowers borne above quite nice foliage. It is adaptable and does well in a sunny, well-drained position. It is reported to be hardy in colder climates. Photo from Shmuel Silinsky.
Geranium viscosissimum is known as sticky Purple Geranium. It is found in drier grasslands and forests from Northern California, into Canada as far east as Saskatchewan. It is hardy to Zone 2 at least. Photos contributed by Paige Woodward.