Position: Full sun to shade
Soil: Moist, well drained
Flowering period: Summer
Eventual Height: 45cm
Eventual Spread: 75cm
Hardiness: USDA Zone 3a-9a
Geranium ‘Johnson’s Blue’ is a deciduous perennial with a spreading habit although in our temperate climate it may retain some foliage throughout the winter. It will spread by rhizomes, as the flowers will not produce viable seed. Its foliage is basal, mid green, with each leaf having seven lobes, which are themselves lobed with a serrate margin. In summer it will bear loose cymes of saucer shaped lavender blue flowers, which are tinged pink at their centres.
Geranium ’Johnson’s Blue’ is synonymous with Geranium himalayense x pratense, but since this is one of the oldest Geranium crosses and it hybridises so easily this provenance is questionable. As the name suggests it is a cross between Geranium himalayense (from south west China) and Geranium pratense (from Europe).
The etymological root of the binomial name Geranium is derived from the Greek geranos, meaning ‘crane’; referring to the beak-like fruit.
Geranium ’Johnson’s Blue’ may be useful to the landscape architect as a free flowering semi deciduous ground cover plant. It is appropriate for prairie type or cottage garden style planting schemes. It will also tolerate dry shade and short periods of drought.
The Royal Horticultural Society have given Geranium ’Johnson’s Blue’ their prestigious Award of Garden Merit.
Geranium ’Johnson’s Blue’ will tolerate almost any soil conditions; it will be happy in acid, neutral or alkaline pH levels, in loam, sand, chalk or clay based soils in a sheltered or exposed location facing any aspect.
Ecologically, Geranium ’Johnson’s Blue’ will attract pollinating insects such as butterflies and honey bees and the larvae of some species of Lepidoptera will feed on its foliage.
Geranium ’Johnson’s Blue’ requires little to no maintenance, Flowered stems and old leaves may be removed to encourage new growth. This plant may be divided in spring or autumn to increase numbers.