It is six years since I started this blog, and during that time I haven’t written about any of my favourite groups of plants, the cranesbills (genus Geranium, in the family Geraniaceae). It is time I made amends.
We have about a dozen species of Geranium in our garden, including cultivated varieties and “weeds”, like Herb Robert (Geranium robertianum) and Shining Cranesbill (Geranium lucidum), that I allow to grow and self-seed, pulling out any that are in the wrong place. Bloody Cranesbill, Geranium sanguineum, is one of my favourite cranesbills.
I first encountered Bloody Cranesbill in The Burren in Ireland, where it grows in gaps (grikes) in limestone pavements. Then, when we bought our first house in Norwich, it was growing in the back garden, and we moved some to our current garden when we moved here nearly five years ago. Since then I have seen Bloody Cranesbill on low cliffs along the Northumberland coast and on roadsides in Cumbria. My experiences of the plant tie in with the description of the plant’s distribution in the Online Atlas of the British and Irish Flora: it can be found in grassland, rocky woodlands and on coastal cliffs, where it prefers base-rich soils, but it can often be found as a garden escape. Bloody Cranesbill also grows in other parts of Europe and Asia, as far north as southern Finland. And in America – according to Missouri Botanical Garden, Geranium sanguineum is “perhaps the most common species of geranium grown in the U.S. today”.
Bloody Cranesbill is a clump forming perennial with deeply divided palmate leaves. The flowers have five overlapping petals and appear from May to August, with their peak in June and July. In the commonest form of the plant these are magenta, ageing to a purplish-blue. According to Richard Mabey (Flora Britannica p272), the name “bloody” and the specific name “sanguineum“, which means the same, originally came from the colour of the plant’s stalk-joints. The flower stalks, seed capsules and leaves also turn red in autumn. The First Nature website says that it is the colour of the stalks and seed capsules that give rise to the name, while Wikipedia suggests that it may be the autumn leaf colour. The specific name “Geranium” and the English name “Cranesbill” both refer to the shape of the plant’s seed capsule.
When I selected plants for Grapes Hill Community Garden in 2011, I ordered several Geranium sanguineum. I was a little surprised when these produced flowers with crinkled pink petals, rather than magenta. I discovered we had bought Geranium sanguineum ‘Striatum’, Striped Bloody Cranesbill. It was actually a pleasant surprise: it is a very pretty flower. I now grow both forms in our back garden. I hope to visit Walney Island in Cumbria one day to see G. sanguineum ‘Striatum’ growing in the wild. (Its older name of Geranium sanguineum var. lancastrense is sometimes used by gardeners and refers to its place of origin – before boundary changes in 1974 Walney Island was part of Lancashire.
Nurseries such as The Plantsman’s Preference in South Norfolk stock many other varieties. I have also tried G. sanguineum ‘Max Frei’, which has magenta flowers but is a more compact plant, suited to banks and rockeries.
Geranium sanguineum is a superb garden plant. It is good ground cover but it isn’t invasive. Clumps can be split every few years and new plants can also be grown from seed. The RHS and Gardeners’ World websites give advice to growers. I have grown Bloody Cranesbill in semi-shade and sunshine, on loamy soil and sandy loam. The ideal growing medium is “moist but well drained“, if such a soil exists.
One very good reason for growing Geranium sanguineum is its wildlife value, as the flowers are attractive to a range of solitary bees. In our garden last summer the flowers were visited by several species, including the Patchwork Leafcutter Bee (Megachile centuncularis), the White-jawed Yellow-face Bee (Hylaeus confusus), the Large Narcissus Hoverfly Merodon equestris, the Blue Mason-bee (Osmia caerulescens) and Small Scissor Bee (Chelostoma campanularum).
Although Bloody Cranesbill isn’t thought to be poisonous, it isn’t considered to be edible either. The Plants For A Future website doesn’t list it but it has an entry for its relative Meadow Cranesbill, Geranium pratense. Under “edible uses” it says “none known”.