Annuals come into their own this month and none more colourful than the Cosmos which was introduced into this country in 1800 from Mexico. These big, bright and beautiful daisy-like flowers come in many colours and heights. The most common variety C. bipinnatus with large yellow-eyed daisy flowers in the burgundy-red-pink-white colour range include the taller ‘Purity’ that will grow to 1.2m and suited to the back of the border. The shorter varieties like ‘Apollo’ are good to grow in containers and new types include ‘Xanthos’ the first yellow-flowered variety. Keep the containers fairly large though as even the shortest plants reach 45cm tall and as much across.
Varieties derived from C. sulphureus have smaller flowers in scarlet, orange and yellow shades set against slightly broader, darker leaves. [unfortunately I do not have any images of this type]
C. atrosanguineus is the Chocolate cosmos which is hugely popular with richly chocolate-coloured, and chocolate-scented, flowers. This is a half-hardy perennial that develops tubers like those of a slimline dahlia and may need to be overwintered indoors. This is also a good candidate for containers.
Cosmos enjoy plenty of sunshine and any reasonable soil, although rich, moist conditions encourage exuberantly leafy growth at the expense of flowers. If you ensure to deadhead throughout summer into early autumn, you’ll continue to get beautiful flowers right through the season.