How to grow Geranium
From the Greek geranos, a crane, because the seed pod resembles a crane’s head and beak (Geraniaceae). Crane’s-bill. A genus of hardy herbaceous summer-flowering perennials with lobed or cut leaves, widely distributed over the temperate regions of the world. They are easily cultivated, free flowering and some are useful rock garden plants, others good border plants.
Species cultivated G. aconitifolium, 15-18 inches, leaves finely divided, flowers white
with black veins, May and June. G. anemonifolium, 1-2 feet, pale purple, May and June, may need winter protection. G. argenteum, 4 inches, clear pink, summer, scree plant. G. atlanticum, 9 inches, purple, red-veined, summer. G. candidum, 1 foot, spreading, sprawling habit, white, crimson-centred, cup-shaped flowers, summer. G. celticum, 4 inches, white, all summer. G. cinereum, 6 inches, pale pink, June to August; vars. album, white; subcaulescens, cerise, dark-centred, May to October. G. collinum, 9-12 inches, red to purplish-violet, May and June. G. dalmaticum, 6-9 inches, pink, summer; var. album, white. G. delavayi, 1 foot, crimson, summer. G. endressii, 9-18 inches, light rose, June to October or later; cultivars include ‘A. T. Johnson’, silvery-pink; ‘Rose Clair’ salmon, veined purple; `Wargrave Variety’, deeper pink. G. grandiflorum, 1-11 feet, blue, red-veined, spring to autumn; var. alpinum, 9-12 inches, deeper blue, larger flowered. G. ibericum, 1 foot, violet-purple, all summer. G. kotschyi, 9 inches, soft purple, darker veined, early summer. G. macrorrhizum, 18 inches, red to purple, all summer; var. album, white. `Ingwersen’s Variety’, 9-12 inches, rose-pink, is a fine cultivar. G. napuligerum (syn. G. farreri), 4 inches, soft pink, May and June, scree plant. G. phaeum, mourning widow, 18 inches, dark purple, May and June. G. platypetalum, 2 feet, deep violet, red-veined, June and July. G. pratense, meadow crane’s-bill, 2 feet, blue, May to September, native ; vars. album, white; flore-pleno, double blue; roseum, 1 feet, rose-pink. G. psilostemon (syn. G. armenum), 2 feet, magenta-crimson, dark-centred, May and June. G. pylzowianum, 3-4 inches, clear pink, early summer. G. renardii, 9 inches, white, purple centred, summer. G. sanguineum, bloody crane’s-bill, 6-24 inches, blood-red, summer, native; vars. album, white; lancastriense, 4 inches, pink; prostratum, 6 inches, rosy-pink. G. sessiliflorum, prostrate, white and purple, summer; var. nigricans, dark leaves. G. stapfianum var. roseum, 4 inches, crimson-purple flowers. summer, richly coloured autumn foliage. G. striatum, 15 inches, pale pink, reddish veins, May to October. G. sylvaticum, 18 inches, purple-blue, summer, native; vars. album, white; roseum, rose-pink. G. tuberosum, 9 inches, purplish, May; var. charlesii, pink. G. wallichianum, 1 foot, purple, August and September; ‘Buxton’s Blue’, deep blue with a white eye, is the cultivar usually offered. G. yunnanense, 12-15 inches, white, purple-veined, summer.
Cultivation In general, the crane’s-bills are easy to grow, although, as noted above, some of the dwarf species need scree conditions in the rock garden. The others will grow in any kind of soil; most of them do best in a sunny position although G. endressii, one of the finest, as it produces its pink flowers over a very long period, will tolerate a good deal of shade, as will G. aconitifolium, G. macrorrhizum and G. phaeum. The taller species are apt to look a little untidy after they have flowered, and benefit from a trim over, just above the leaves to remove the spent flower stems. This will often result in a second flush of flowers being produced, especially if it is done before the seeds ripen. Most species form clumps (a few are tap-rooted) and these are very easily propagated by division in autumn or spring. With those that form vigorous, wide-spreading clumps, such as G. endressii and G. grandiforum, it is not even necessary to dig up the clumps in order to divide them; it is sufficient to cut away pieces from around the clump and replant these. Seeds may also be sown, either under glass in the cold frame or greenhouse or out of doors, in March or April.