Cosmos atrosanguineus is a summer flowering perennial. Plants produce slender flowering stems, which are each topped with small dusky chocolatey maroon coloured, open flowers. Like other Cosmos, Cosmos atrosanguineus flowers are popular with bees, butterflies, and other pollinating insects. Deadhead the flowers as they fade, to prolong your plant’s flowering and help your plant to produce more flowers.
I enjoy growing Cosmos atrosanguineus; this is a lovely plant to have in your garden. I appreciate the rich, velvety look of this plant’s maroon-chocolate coloured flowers, but for me, one of the best things about Cosmos atrosanguineus is the scent of this plant’s flowers. Cosmos atrosanguineus blooms produce an absolutely gorgeous fragrance, it’s just like chocolate! I find that this plant’s scent varies a little from plant to plant – so if you’re choosing a plant at your local nursery, make sure to choose one with a perfume you enjoy. Although do remember that a flower’s age will affect the bloom’s fragrance; newer flowers often have a more pronounced fragrance than older blooms.
Plant Cosmos atrosanguineus in a warm, sunny spot. This perennial flourishes in moist, but well drained soil. This is quite a delicate looking plant; Cosmos atrosanguineus grows to around 60cm (2ft) tall.
Cosmos atrosanguineus plants are hardy down to a maximum of around -5C. The hardiness of a plant depends of course of the particular plant’s growing conditions – plants grown in wetter soils will not survive as long, as those grown in free draining soil or compost. If you live in a colder area of the country, or if your soil tends to remain waterlogged in winter, you may want to lift your plants and move them somewhere dry and frost free, over winter. Alternatively, grow your Cosmos atrosanguineus plants in containers and move them into a porch or a sheltered area of the garden, over winter.