10 fast flowers to grow from seed

Half-hardy annuals are the perfect choice for gardeners in a hurry. Fast growing and colourful, many half-hardy annual species have the stature to perform centre stage in summer planting schemes.

Despite their exotic looks, half-hardy annuals are surprisingly easy to grow, though you do need to raise them from seed, indoors. Growing half-hardy annuals from seed will give you a much wider choice of varieties than you’ll have if you buy ready-grown plants, and some species will flower in as little as 12 weeks.

Prick out seedlings into pots or multi-cell trays and grow them on into sturdy plants, ready to drop into border gaps. Dot single plants as accents through your borders, or plant generous drifts between perennials, providing a contrast of foliage and colour.



With soft, ferny foliage and delicate blooms, cosmos mingles well in any border. Regular cutting keeps blooms coming. Height 40-90cm. Flowers in 14 weeks.


There are many colours of Nicotiana to choose from, including white, lime green and purple. Wonderful scented foliage and flowers. Height: 90-150cm. Flowers in 16 weeks.


Often relegated to greenhouses or border edges, large-flowered african varieties of Tagetes also make a striking centre piece. Height: 60-90cm. Flowers in 16 weeks. ('Tall Scotch Prize' is pictured here.)


With deep-red maple-like leaves and spiky fruits, the exotic castor oil plant, Ricinus communis, really earns its space in any border. Height: 1-2.5m Flowers in 16 weeks.


Spider flowers, Cleome, have impossibly intricate blooms in white or pink. Combine with large dahlias in pastel shades. Height: 90-120cm. Flowers in 14 weeks.


Zinnias are available in many vibrant colours, so there’s one of these zingy daisies to suit every colour scheme. Also good as cut flowers. Height: 30-90cm. Flowers in 16 weeks.


Annual climbers, like this cup-and-saucer vine, Cobaea, quickly cover unsightly walls. They can also be trained to make a feature up an obelisk. Height: 6m. Flowers in 16 weeks.


Amaranthus bear fuzzy flowers in bold spikes or weeping tails. Choose from plants with red or green flowers and foliage. Height: 45-120cm. Flowers in 12 weeks.


Very quick and easy to grow, nasturtiums produce long, trailing stems covered in neat, round leaves and bright flowers. Spread: 35-100cm. Flowers in 10-12 weeks.

Verbena x hybrida

Mildew-resistant Verbena x hybrida 'St George' has deep green foliage and a spreading habit. Stunning red and white flowers. Height: 15-25cm (6-10in). Flowers in 14 weeks.


Discover more ideas and inspiration

Related content

Creating a summer pot

How to grow annual climbers from seed

How to sow sweet pea seeds

Related offers


Subscriber only content

Save £11 on trilliums

Trilliums are great for shady gardens. Save £11 when you buy three trillium plants for just £22, plus receive 50 free Anemone blanda bulbs with your order.

Unlock now


Subscriber only content

Perfect tulip collections

Enjoy harmonius colour combinations next spring with Sarah Raven's tulip collections. You'll get free p&p, worth £4.95, on tulip collections with this offer.

Unlock now


200 free spring bulbs

Claim your collection of 200 spring bulbs, including six popular varieties (worth over £24), for free. Just pay £5.65 for postage.

Order now