Overview
Allamanda cathartica 'Williamsii' is a climbing conservatory greenhouse in the genus Allamanda, part of the Apocynaceae family, with evergreen foliage. Allamanda cathartica 'Williamsii' grows best in full sun, and tolerates loam and sand soils and acid and neutral pH. Its UK hardiness is rated H1b. Suggested uses include patio and container plants, sub-tropical and wall side borders.
About
Allamanda cathartica 'Williamsii' is a climbing evergreen shrub cultivar within the Allamanda genus, known for their scrambling growth and large trumpet-shaped flowers in terminal clusters. This cultivar thrives in full sun and prefers a sheltered position with fertile, well-drained loam or sandy soil that is moist but well-drained, tolerating acid to neutral pH levels. Suitable for patio and container planting as well as sub-tropical and wall side borders, it is best grown in south, east, or west-facing aspects. It is hardy to UK zone H1b and flowers in spring and summer.
Growing conditions
Best soil and position for Allamanda
- Sunlight
- Full sun
- Soil type
- Loam, Sand
- Soil pH
- Acid, Neutral
- Soil moisture
- Moist but well-drained
- Aspect
- South-facing, East-facing, West-facing
- Exposure
- Sheltered
- UK hardiness
- H1b
Plant details
Allamanda cathartica 'Williamsii' size, habit and characteristics
- Plant type
- Conservatory Greenhouse
- Habit
- Climbing
- Foliage
- Evergreen
- Suggested uses
- Patio and container plants, Sub-tropical, Wall side borders
Care notes
Pruning and caring for Allamanda cathartica 'Williamsii'
- Propagation
- Seed, greenwood cuttings
- Pest resistance
- Glasshouse red spider mite, glasshouse whitefly
- Disease resistance
- Generally disease-free
Frequently asked questions
Where is the best place to plant Allamanda cathartica 'Williamsii'?
Allamanda cathartica 'Williamsii' prefers full sun. It suits sheltered positions.
What soil does Allamanda cathartica 'Williamsii' need?
Allamanda cathartica 'Williamsii' grows best in loam and sand soil. It prefers acid and neutral soil. Aim for soil that stays moist but well-drained.
Is Allamanda cathartica 'Williamsii' hardy in the UK?
Allamanda cathartica 'Williamsii' has an RHS hardiness rating of H1b, meaning it needs subtropical warmth of 10–15°C and must be grown under glass in the UK.
How do I propagate Allamanda cathartica 'Williamsii'?
Seed, greenwood cuttings.
