Hibiscus Seeds

Roselle (Hibiscus sabdariffa) is the plant behind Egypt's beloved karkade. After the pale, creamy flowers fade, the plant forms plump, fleshy calyces in a deep crimson red that are the prized part of the harvest. Steeped hot or cold, they make a brilliantly tart, ruby-coloured drink with a cranberry-like edge, and the same calyces lift jams, syrups, sauces and herbal teas. Tall and bushy with handsome reddish stems, it doubles as a striking ornamental in the late-season garden.

Planting

Sow in spring (March-April), as roselle needs a long, warm, frost-free season of about six months. In cool conditions start seeds in flats under cover and transplant after 4-6 weeks, once all frost has passed. Soak seed for around 24 hours to speed sprouting, then sow about 1.3 cm deep into moist soil. Germination takes 5-10 days at a soil temperature near 24-29 C. Space plants about 45 cm apart in rows roughly 90 cm apart, and give them full sun.

Fertilizing

Work compost into the bed at planting and feed about 2-4 weeks after planting, ideally guided by a soil test. Avoid excess nitrogen, which pushes leafy growth at the expense of flowers and calyces; a phosphorus source instead supports good calyx development.

Care

Keep the soil well-drained but consistently moist, watering generously through dry spells so plants never dry out while actively growing. When direct-seeding, thin to the strongest seedling once plants reach 5-8 cm tall. Rotate planting sites and mulch to suppress root-knot nematode, the most serious problem; watch for foot, stem and root rots in wet soil and spider mites in hot, dry weather. Flowering begins as autumn days shorten; pick the calyces while plump, tender and rich crimson, about 8-10 days after they form.