Cosmos are half-hardy annuals with daisy-like flowers that are easy to grow from seed and are incredibly long flowering, from midsummer until the first frosts.


They're very useful for filling gaps in summer borders, look good in meadow-style planting schemes and are ideal for container displays. They make fantastic cut flowers and are great for wildlife, too – they attract bees, butterflies and hoverflies.

Discover 10 colourful cosmos to grow.

For the best results, sow seeds in March or April. Harden off the seedlings before planting out in a sunny spot, and deadhead the spent blooms regularly to prolong flowering.

Cosmos look good with many different plants – here are eight inspirational combinations.

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Cosmos and calendula

Here, the magenta Cosmos bipannatus 'Dazzler' is grown in drifts, combined with a tall marigold, Calendula officinalis 'Indian Prince'. Both are easy to grow from seed and make excellent cut flowers.

French marigolds growing with cosmos
Magenta cosmos with contrasting orange marigolds

Cosmos and zinnia

In this all-pink combination, the daisy-like flowers of pale pink cosmos are enhanced by magenta zinnias. Discover eight essential border daisies to grow.

Cosmos and zinnia
Pale-pink cosmos complemented by magenta zinnias

Cosmos and tobacco plant

White cosmos and tobacco plant (nicotiana) are two essential components of a white garden. If you mostly enjoy your garden in the evening after work, white plants work really well as they show up well in the fading light. Discover how to grow nicotiana from seed.

Cosmos and tobacco plant
White tobacco plant flowers with white cosmos

Cosmos and dahlias

Cosmos and dahlias both bring colour and long-lasting blooms to gaps in borders and both are staples of the cutting patch. As their flower forms can be quite similar, grow contrasting colours. Browse our plant database for over 70 beautiful dahlias to grow.

Cosmos and dahlia
Bright-pink cosmos with pale orange dahlias

Cosmos, thalictrum, nepeta and hardy geranium

In this blue and white display, annuals and perennials combine – the white cosmos is combined with the spray like white flowers of Thalictrum delavayi 'Album', the blue flowers of catnip (Nepeta racemosa 'Walkers Low') and Geranium 'Orion'.

Cosmos with blue flowers
White cosmos and thalictrum with blue nepeta and hardy geranium

Cosmos, French marigold and bidens

Orange and white is quite an unusual flower combination – the yellow/orange centre of the cosmos complements the orange of the double flowers of French marigold (tagetes) and tickseed (bidens).

Cosmos and bidens
White cosmos with orange marigolds and tickseed

Cosmos and eryngium

Cosmos bipinnatus 'Antiquity' has flowers that start off crimson, then fade slightly. They contrast with the icy blue, spiky flowers of Eryngium x zabelii 'Big Blue'.

Cosmos and eryngium
Pink cosmos paired with blue eryngium

Cosmos and Verbena bonariensis

Cosmos look great in meadow-style planting schemes. Here they are paired with airy Verbena bonariensis. Both plants will flower for months on end.

Meadow with cosmos
Mauve and white cosmos paired with purple verbena