Cosmos atrosanguineus
chocolate cosmos
This perennial dies back to below ground level each year in autumn, then fresh new growth appears again in spring.
- Position: full sun
- Soil: moderately fertile, moist but well-drained soil
- Rate of growth: average
- Flowering period: June to September
- Hardiness: half hardy (will need winter protection)
These velvety, dahlia-like, chocolate-maroon flowers have a delicious aroma, reminiscent of the best Belgian chocolates. One of our recommended plants, they're particularly suitable for a sunny, exotic garden or a planting scheme based on 'hot' colours.
Plant Cosmos atrosanguineus in frost-free conditions, in a sunny spot with well-drained soil, spacing the plants 30-40cm (12-15in) apart. Water thoroughly, keeping the soil moist but not waterlogged, and mulch to retain moisture and suppress weeds. Fertilise in spring and mid-summer, and deadhead spent blooms to encourage continuous flowering. In cooler locations, dig up the tubers in autumn, reduce the stems to within 5cm (2in) of the roots, and store them in a cool, dry place for replanting in spring. Alternatively, mulch with a thick layer of compost over the winter to protect the plants.