Basic information about Hardy Geraniums. Includes Origin, Growing & Cultivation, Common Pests & Diseases, Interesting Facts & Uses, and Garden Design Tips.
The botanical name, Geranium, is derived from the Greek word ‘geranos’ or crane, referring to the shape of the seed pod (which in some species is long and shaped like a crane’s bill.)
The common name, Cranesbill, also alludes to this distinctive seed pod.
Geranium is a huge genus with over 500 species, native throughout most of the world’s temperate regions. Most are concentrated in in the eastern Mediterranean.
Growing and Cultivation
Most geraniums prefer full sun and well-drained, neutral to slightly acid soils. Some varieties are sensitive to the heat of afternoon sun, and would like to be shaded at that time. Once established, shearing back to a few inches of base after flowering is recommended to keep them tidy as well as encourage rebloom. Geraniums are not fussy with their soils; only the most waterlogged with have detrimental effects on your plants. Established plants only require watering during drought conditions, though water-retentive mulch (like wood chips) is appreciated as long as it is not placed over or too near the crown of the plant (where stems meet roots at soil level). High potassium fertilizer will promote abundant flowering. Geraniums prefer to go into winter on the dry side, and to stay relatively dry throughout that season. These plants should be divided every 3 to 5 years, to prevent or treat center die-out.
Common Pests and Diseases
Though usually very pest and disease resistant, geraniums can sometimes develop mildews (whitish-gray powder on leaves) and rust (bright orange powder on underside of leaves) – cutting and disposing of infected parts (do NOT compost!) and treating with fungicides is recommended in these cases, as well as improving drainage by amending soil with perlite, bark, coarse sand or other materials.
They are deer resistant, though rabbits will munch on young shoots in spring.
Interesting Facts and Uses
Geraniums are often confused with their annual or half-hardy cousins, the frequently potted Pelargoniums, who are also commonly called geraniums, to the dismay of botanists and horticulturalists and the confusion of gardeners worldwide. This can be traced to the fact that Linnaeus originally classified them in the same genus; Charles L’eritier divided them into Geraniums and Pelargoniums in 1789, but the sharing of the common name persists to the present day.
Some geraniums (G. sanguineum, G. pratense, and G. cantabrigiense in particular) have truly spectacular fall colors, displaying shades of red, orange, yellow and even purple!
Geranium cinereum ‘Ballerina’ received the UK Royal Horticultural Society’s Award of Garden Merit in 1993. Many other geraniums have also received this prestigious award.
The seed pods of geraniums are what is called explosively dehiscent – they use a buildup of kinetic pressure to burst and physically fling their seeds away from the parent plant.
Essential oil is prepared from Geranium macrorrhizum for use in aromatherapy and herbal medicine.
Some geraniums attract bees and butterflies, making them a good addition to a pollinator-friendly garden.
Garden Design Tips
With so many varieties of differing heights, colors, and growth habits, geraniums have a multitude of uses in the garden!
Taller varieties (Like G. pratense or G. sanguineum hybrids) blend well into perennial borders and complement iris, Astilbe, or other tall, narrow spire-like plants, as well as daylily, coreopsis and roses. They can be used to fill in or take over from peonies that are finished with their floral display.
The shorter, spreading varieties (such as G. cinereum or G. macrorrhizum hybrids) do wonderfully in rock gardens, retaining walls, walkway edges, and are commonly planted below roses to hide their ‘knees’.
To purchase varieties of Geranium, please visit our Sun Companion Plants Page.