About
Geranium thunbergii, the Japanese cranesbill, is a vigorous, semi-evergreen perennial to around 30 cm with trailing to ascending stems and light-green, lobed leaves with bronze markings in the notches. Loose sprays of small, pink, purple or white flowers with purple veining are produced in late summer and sometimes into early autumn. A useful and ornamental cranesbill for a sunny or partly shaded border.
About the genus
Geranium, the cranesbills, are annuals, biennials and herbaceous or evergreen perennials with rounded, usually palmately lobed or divided leaves and loose clusters of rounded, five-petalled flowers in white, pink, purple or blue. Among the most versatile and garden-worthy of all perennial genera.
Growing conditions
SunlightFull sun, Partial shade
Soil typeChalk, Clay, Loam, Sand
Soil pHAcid, Alkaline, Neutral
Soil moistureMoist but well-drained, Well-drained
AspectEast-facing, South-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH5
Plant details
Plant typeHerbaceous Perennial
HabitTrailing
FoliageSemi evergreen
Height0.1-0.5 metres
Spread0.1-0.5 metres
Time to full height2-5 years
Suggested usesCottage and informal garden, Wildlife gardens, Coastal
Native toJapan, Korea
Care notes
CultivationThrives in sun in well-drained soil, but will tolerate a range of soils and positions, except waterlogging
PruningRemove flowered stems and old leaves to encourage the production of fresh growth
PropagationPropagate by seed, or by division, trailing stems will sometimes root at the nodes
Pest resistanceMay be susceptible to vine weevil larvae, geranium sawfly larvae, capsid bug, slugs and snails
Disease resistanceMay be susceptible to downy mildews and virus diseases, and to powdery mildews in dry conditions