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Cosmos atrosanguineus

Chocolate cosmos

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From 10 ratings

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Key information

Plant type

Tender perennial

Flower colour






Skill level


Cosmos atrosanguineus

Plant details

Formerly called Bidens atrosanguinea and comparatively unknown, this tender Mexican perennial is now a fashionable late summer highlight in warm borders, as much for its scent of vanilla and hot chocolate as for the dusky brownish-red blooms. As with most cosmos varieties, the blooms resemble small single dahlias, and its culture is similar too, for it has a tuber which, in mild gardens, may be planted at least 15cm (6in) deep and left in the ground with winter protection, or is more usually lifted in autumn for drying and storage.

Family: Asteraceae

Genus: Cosmos

Species: atrosanguineus

Plant type: Tender perennial

Flower colour: Red

Foliage colour: Mid-green

Feature: Flowers

Sun exposure: Full sun

Soil: Well-drained/light, Clay/heavy, Chalky/alkaline

Hardiness: Tender

Skill level: Experienced

Height: 90cm

Spread: 45cm

Time to plant seeds: March to May

Time to divide plants: March to April

Flowering period: June to September

Reader reviews


Mine are still flowering like mad. I love this plant. I have them in pots by my patio door, and this along with the vanilla-ey evening primrose make my garden smell like a sweetshop!


I'm growing this Cosmos for the first time this year and I'm really looking forward to its sweet smelling blooms. I have planted it in a large tub so that come winter I can place it in a safe frost free place.


I have grown a Chocolate Cosmos from a tuber for the first time this year and all I can say is WOW - It's in a well drained raised bed in full sun, it suffered slightly in the cold windy conditions we had earlier in the summer but since late July it has become the star of the garden and it is still flowering it's socks off and the smell mmmm! Hope to overwinter the tuber.


I have a chocolate Cosmos in a pot that we have bought into the conservatory. Will it over winter without removing the tubers in the pot with just cutting the plant back?


I don't want to loose my Chocolate Cosmos, planted this summer in a border. What is the best way to overwinter it?


I am new to gardening and was bought one of these lovely plants but I'm worried that it may suffer over the winter, should I lift it now to protect it from the winter conditions?


I managed to overwinter mine for the first time . As i don't have a proper greenhouse I wrapped the planter in fleece. This worked fine and new shoots emerged!!!! The rain came and I started bringing it in at night. One night I forgot And the slugs ATE THE LOT!! That was the end of the plant.
So this does work if you're not forgetful


I have never yet managed to overwinter a Chocolate Cosmos yet. Last year I left one in the greenhouse with bubble wrap around the pot and another one I took the corm out of the pot wrapped in in fleece in the house and both of them have done nothing at all this year. I just don't know what I am doing wrong its most frustrating.


i have grown annual cosmos, but this year am looking into buying the bareroot, i have been reading some of your tips and the way to store, i suppose its give and take like dahlia tubers i store them in a box with wood shavings,we shall see

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