Overview
Onosma arenaria is a clump forming alpine rockery in the genus Onosma, part of the Boraginaceae family, with evergreen foliage. Onosma arenaria grows best in full sun, and tolerates most soils and any pH. Its UK hardiness is rated H4. Suggested uses include rock garden, gravel garden, cottage and informal garden and city and courtyard gardens.
About
Onosma arenaria is a clump-forming evergreen perennial from the genus Onosma, known for rosette-forming plants native to arid, rocky Mediterranean and western Asian regions. This alpine rockery plant thrives in full sun and well-drained soils such as chalk, loam, or sand, tolerating a range of soil pH from acid to alkaline. It is hardy to UK zone H4 and is suitable for rock gardens, gravel gardens, and informal or courtyard settings. The plant features slender, hairy green leaves and produces elongated, drooping tubular flowers in spring and summer.
Growing conditions
Best soil and position for Onosma
- Sunlight
- Full sun
- Soil type
- Chalk, Loam, Sand
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Well-drained
- Aspect
- South-facing, West-facing
- Exposure
- Exposed, Sheltered
- UK hardiness
- H4
Plant details
Onosma arenaria size, habit and characteristics
- Plant type
- Alpine Rockery, Herbaceous Perennial
- Habit
- Clump forming
- Foliage
- Evergreen
- Suggested uses
- Rock garden, Gravel garden, Cottage and informal garden, City and courtyard gardens
Care notes
Pruning and caring for Onosma arenaria
- Propagation
- Seed, sown in containers in an open frame in autumn
- Pest resistance
- Aphids, Glasshouse whitefly
- Disease resistance
- Generally disease-free
Frequently asked questions
Where is the best place to plant Onosma arenaria?
Onosma arenaria prefers full sun. It suits exposed and sheltered positions.
What soil does Onosma arenaria need?
Onosma arenaria is adaptable and grows happily in most soil types, including chalk, loam and sand. It is happy in soil of any pH. Aim for soil that stays well-drained.
Is Onosma arenaria hardy in the UK?
Onosma arenaria has an RHS hardiness rating of H4, meaning it is hardy through an average UK winter, tolerating -10 to -5°C.
How do I propagate Onosma arenaria?
Seed, sown in containers in an open frame in autumn.