21 annual flowers for beds, pots and balcony boxes – including Cosmos

Perennials are brilliant, but they take time to establish. Annual flowers, on the other hand, deliver a burst of colour at speed. Many can be sown straight where they’re to grow, will flower right through summer, and look just as good in a vase. Here are 21 favourites that make a real statement in borders, pots and balcony boxes - including the ever-popular Cosmos.

Why annual flowers are in such demand right now

Annuals grow from seed to flower in a single season, then finish. It may sound short-lived, but it comes with clear upsides: you can redesign every year, fill gaps quickly, and play with colour without being tied to the same choice for years.

“Annuals are the quickest way to turn a garden from ‘bare’ to ‘postcard-worthy’ in just a few weeks.”

Many varieties are also excellent for insects. Bees, bumblebees and butterflies benefit from gardens that keep producing fresh blooms from spring right through to the first frost - and that’s exactly where the following plants really shine.

The 21 most beautiful annual flowers at a glance

Flower	Position	Flowering period (approx.)	Stand-out feature
Sweet pea	Sun to partial shade	Late spring to early summer	Strong fragrance, ideal for supports
Sweet alyssum	Sun to partial shade	Spring to first frost	Ground-hugging carpet with a honey scent
Ammi (bishop’s weed)	Full sun	Summer	Fine white umbels for bouquets
Gerbera	Partial shade to sun	Spring to autumn	Excellent cut flower, vivid colours
Nasturtium	Sun to partial shade	Summer to autumn	Edible flowers, easy from seed
Love-in-a-mist (Nigella)	Sun	Spring or autumn	Self-seeds, delicate look
Cornflower	Sun	Early to mid-summer	Classic cornflower blue, great for cutting
Poppy	Sun	Late spring to early summer	Silky petals, very straightforward
Zinnia	Sun	Summer to autumn	Many colours, attracts butterflies
Petunia	Sun	Spring to autumn	A container classic, flowers until the first frost

We’ll look at the remaining eleven flowering stars in detail in a moment.

Romantic, playful or bold - there’s something for every garden style

Fragrant climbers and groundcovers

Sweet peas climb gracefully up fences, obelisks or balcony railings. They really get going in cooler spells, and many varieties give off an intense fragrance. Key tip: pick regularly or remove spent flowers, and you’ll keep encouraging fresh blooms.

Sweet alyssum

---