For as long as most of us have been gardening, only one form of chocolate cosmos, Cosmos atrosanguineus, has been available and that was a sterile form that never set seed and had to be propagated by cuttings or in the laboratory using tissue culture.
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Now, things have changed. There are two new varieties to grow from seed this year and a new large-flowered form that is propagated by tissue culture.
Seed of straight Cosmos atrosanguineus from Plant World Seeds is in short supply but will give you plants in a variety of styles – dwarf and bushy or tall and good for cutting – and flowers that vary in colour from almost black to rich red and with petals in a variety of shapes.
‘Black Magic’ (right), developed in Germany from one single seedhead received from a private garden in New Zealand in 2005, also varies in its colour and flower form. Some plants have narrow petals, in others the petals are broader; some are rich chocolate in colour, some are redder; some have that familiar chocolate scent while some are more vanilla scented.
Finally, we have Eclipse ('Hamcoec') (right). Developed in New Zealand by plant breeder Keith Hammett, who is especially well known for his sweet peas and dahlias, at around 5cm (2in) across the flowers are larger than those of any other variety. They have a distinct reddish black colour with broad petals making a very full flower - and that familiar rich chocolate fragrance.
Expect more variations and improvements on the chocolate cosmos later this season.