September is the ideal time to sow hardy annuals for flowers in spring and summer the following year. The seeds can also be sown in spring, but sowing in autumn often results in earlier flowers and more robust plants.
Sowing hardy annuals is easy – either sow in rows, or broadcast the seed on a prepared seedbed. Find out how to sow hardy annuals outside.
Related content:
- Give borders an autumn boost
- Five autumn perennials for September
- Four autumn wildlife gardening jobs
Here are five hardy annuals to sow in September.
English marigold (Calendula officinalis)

English marigold has deep orange petals, which are perfect for a hot border or for cutting. It’s very easy to grow – from an autumn sowing it should flower from May. Allow some seedheads to dry so that you save the seed; it may also self seed, without becoming a nuisance.
Love-in-a-mist (Nigella damascena)

Nigella damascena is a cottage garden favourite and makes a lovely cut flower. Its dried seedheads are attractive, too.
Cornflower

Centaurea cyanus often forms part of pictorial and annual meadow schemes, and makes an excellent cut flower. The blue-flowered variety is the most commonly grown, but different cultivars may have red, pink, white and dark purple flowers.
Queen Anne’s Lace (Ammi majus)

Ammi majus is best sown in autumn, resulting in bigger, better flowers in early summer. It bears clouds of cow-parsley like blooms and is perfect for cutting.
Poppies

Opium poppy (Papaver somniferum, pictured), field poppy (Papaver rhoeas) and ladybird poppy (Papaver commutatum) can all be sown in autumn.
California poppy

California poppy (Eschscholzia californica) brings swathes of bright orange-yellow to borders and self-seeds readily, so once sown, you will enjoy them every year. Discover how to sow Californian poppy.
Sowing green manure
Autumn is also an ideal time to sow green manures, which protect bare beds from winter rains that can wash away nutrients and break down soil structure. Find out how to sow green manure.
