Cosmos x Dahlia Mexican Black

The Cosmos x Dahlia Mexican Black is a curious tuberous plant, apparently harvested in Mexico, in a wild area. It is said to be the result of a cross-breeding between Cosmos atrosanguineus and Dahlia coccinea, with which it shares various morphological traits. This rare and original plant produces single, slightly fragrant flowers, 6 cm (2in) in diameter, made of a dark brown-purple collar of petals surrounding a beautiful golden yellow center. They bloom in late summer and autumn, above an elegant mound of dark green foliage. Not very hardy, it should be cultivated like a Dahlia, in full sun and in light soil.

The Cosmos x Dahlia Mexican Black is a herbaceous plant with tubers that is quite enigmatic, belonging to the aster family. It resembles more a Dahlia than a cosmos, by the smell of its foliage and its mode of growth. Mainly obtained through vegetative propagation, it develops from a fleshy tuber sensitive to frost and quickly forms a clump of  40 to 50 cm (16 to 20in) in all directions for the foliage, 70 to 80 cm (28 to 32in) for the flowers. The foliage, with few lobes, cut into narrow lobes, somewhat resembles that of peonies. It consists of dark green leaves, slightly tinged with a dull purple, and remains low. The floral stems, tinged with purple-brown, appear in August-September, and until October if faded flowers are regularly removed. The flowers, grouped in heads, consist of slightly crumpled ligulate florets of brownish-purple colour on the periphery and a heart of tubular florets of golden yellow. These heads give off a slight chocolate aroma, especially in hot weather. According to recent molecular studies conducted in 2012, the dark color of the heads is not attributable to cross-breeding with Cosmos atrosanguineus, as it is found in at least 14 Dahlia cultivars.

The Cosmos (x) Dahlia Mexican Black is a little-known variety in France, an accent plant that will not go unnoticed in the ornamental garden at the end of the season. It is sublime when paired with gray and silver foliage. In beds or in pots, it will wonderfully accompany artemisias, bear's ears, or sea cineraria. The warm tone of its flowers enhances pastel colours like the pink or blue of asters or the azure of 'Indigo Spires' sage. It stands out against the acidic green foliage of bipinnate cosmos or Alchemilla mollis.