Geranium pratense Plenum Caeruleum - Meadow Cranesbill

Geranium pratense ‘Plenum Caeruleum’ is a meadow cranesbill with double flowers, valued for its small pompons of light violet-blue. It has the natural habit of the wild species, but with more ornamental flowering on a more compact plant, well suited to border edges. This hardy perennial with a country style thrives in moist soil. Its flowering, between lavender blue and pale mauve, emerges on finely cut foliage.

This cultivar belongs to the Geraniaceae family. It is derived from Geranium pratense, the meadow cranesbill, a Eurasian perennial species found in moist meadows, woodland edges, grassy banks and humid montane areas. 'Plenum Caeruleum’ is a horticultural selection with double flowers. This plant is deciduous: the leaves and stems die back in winter, then regrow from the base in spring. At maturity, it reaches 60 to 70 cm in height when in flower, with a spread of 45 to 50 cm. The leaves are light green to medium green, palmate and deeply divided into toothed lobes. The flower stems rise above the foliage in early summer, between June and July. The flowers, 3-4 cm in diameter, are very double, shaped like small loose pompons, light violet-blue, sometimes tinged with pink in the centre. They lack the open cup appearance seen in the type species: their stamens are transformed into petals, which explains their sterile nature and the absence of spontaneous seedlings. 

In the garden, Geranium pratense ‘Plenum Caeruleum’ is planted in borders, in a perennial bed or at the foot of deciduous shrubs. This perennial tolerates sun if the soil does not dry out; in partial shade, its flowers retain their colour better. You can pair it with Astrantia major ‘Roma’, with Geranium pratense ‘Mrs Kendall Clark’, single and blue, and with Leucanthemum vulgare ‘Maikönigin’ for the freshness of its white daisies. Hardy geraniums are also excellent companions for shrub roses.