Cosmos Seeds

Cosmos seeds – more info

Cosmos are the perfect summer border filler, and make lovely cut flowers too. Sow them under cover in late spring or direct sow into the border after the last frosts.

If you’re growing a taller variety such as a bipinnatus, choose a sheltered spot out of the wind or stake plants with a support cane. In a cut flower border, grow them through pea netting.

Are cosmos annual or perennial?

Cosmos are grown as annuals in the UK as they are not frost-hardy. However, they will self-seed, so if you leave them to their own devices they’ll grow again in the same spot in following years.

How long do cosmos seeds take to germinate?

Cosmos will usually take between seven and 21 days to germinate, going on to flower around six weeks later. A warm environment will encourage faster germination.

How tall do cosmos grow?

Cosmos plants vary in height from dwarf varieties, such as ‘Dwarf Purple Picotee’, which grows to 30cm (12ins), through to tall varieties such as ‘Cupcakes White’, which can reach 120cm (47.2ins).