How to grow Celsia (sel-se-a)
Commemorating the famous theologian and botanist Olaf Celsius of Upsala (Scrophulariaceae). A genus of perennials and biennials treated as half-hardy annuals. They have tall spikes of yellow flowers in summer and look not unlike mulleins (verbascums).
Species cultivated: Greenhouse C. arcturus, 3 feet, perennial, flowers large, yellow with purple anthers, a good pot plant, Crete.
Hardy C. cretica, the Cretan mullein, 4 feet, biennial, fragrant golden-yellow flowers marked with brown, July and August, Mediterranean area.
Cultivation Seed of C. arcturus is sown in March, seedlings are potted on singly in potting compost and flowered in 8-inch pots. Seed of C. cretica is sown in the frame or in the cool greenhouse in March, the seedlings are pricked out and planted out at the end of May. Plants require staking. C. cretica may also be treated as a greenhouse biennial. S.eed is sown in August to flower the following summer. Ample ventilation should be given.