Geranium maderense 'Guernsey White'
giant herb robert 'Guernsey White'
A large evergreen biennial or short-lived perennial, up to 1.2m high, with rosettes of finely divided, fernlike glossy green leaves up to 60cm long. Masses of flat white flowers, with dark pink central eyes, are produced on tall, branching stems in early summer
Buy this plant
Size
Ultimate height
1–1.5 metresTime to ultimate height
1–2 yearsUltimate spread
1–1.5 metresGrowing conditions
Moisture
Moist but well–drained, Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | White Pink | Green | ||
| Autumn | Green | |||
| Winter | Green |
Position
- Full shade
- Full sun
- Partial shade
Aspect
East–facing or North–facing or South–facing or West–facing
Exposure
Sheltered Hardiness
H3Botanical details
- Family
- Geraniaceae
- Native to GB / Ireland
- No
- Foliage
- Evergreen
- Habit
- Bushy, Clump forming
- 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
Accepted
How to grow
Cultivation
In milder areas, grow outdoors in well-drained soil; may benefit from afternoon shade in hot summers. In areas prone to frosts, grow under glass in peat-free, loam-based compost with added sharp sand in bright filtered light. Flowers are produced in the second or third year; after flowering the plant sets seed and dies
Propagation
Propagate by seed, sown in late winter or early spring at 21-23°C
Suggested planting locations and garden types
- Cottage and informal garden
- Gravel garden
- Mediterranean climate plants
- City and courtyard gardens
- Coastal
- Wildlife gardens
- Conservatory and greenhouse
- Flower borders and beds
Pruning
No pruning required. Avoid cutting older leaf stems as they bend downwards; these often serve to support the plant when in flower
Pests
May be susceptible to vine weevil, geranium sawfly, slugs and snails
Diseases
May be susceptible to powdery mildews, downy mildews, rust diseases and virus diseases
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.