Geranium thunbergii

RHS Plant Profile

Japanese cranesbill

Synonyms

Geranium yoshinoi misapplied
Geranium wilfordii misapplied
Geranium nepalense subsp. thunbergii

Herbaceous Perennial

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A vigorous semi-evergreen perennial, to around 30cm high, 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, often with purple veining, are produced in late summer and sometimes into early autumn

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Geraniaceae
Native to GB/Ireland: No
Foliage: Semi evergreen
Habit: Trailing
Genus: Geranium can be annuals, biennials and perennials, herbaceous or evergreen, with rounded, usually palmately lobed or divided leaves, and lax inflorescences of rounded, 5-petalled flowers
Name Status: Correct
Plant Range: Japan, Korea

How to Grow

Cultivation

Thrives in sun in well-drained soil, but will tolerate a range of soils and positions, except waterlogging

Propagation

Propagate by seed, or by division, trailing stems will sometimes root at the nodes

Suggested planting locations and garden types

Cottage and informal garden
Wildlife gardens
Coastal
Flower borders and beds
Underplanting of roses and shrubs

Pruning

Remove flowered stems and old leaves to encourage the production of fresh growth

Pests

May be susceptible to vine weevil larvae, geranium sawfly larvae, capsid bug, slugs and snails

Diseases

May be susceptible to downy mildews and virus diseases, and to powdery mildews in dry conditions