There’s an easy trick that expert gardeners use to fill their backyards with colorful flowers all summer, that brings months of blooms, fast, for very little effort. Annual plants that only live for a season or two are the easiest flowers to grow from seed, and most bloom two or three months after sowing. Their sole aim in life is to make seed to ensure their DNA survives another year, so they germinate quickly and generally don’t need any molly-coddling, making them incredibly easy to grow.

So far, so good – but the clever bit? Savvy gardeners pick unusual varieties of these staple species so the flowers look far more glamorous than their easy-grow nature warrants. And there are plenty to choose from! Because of their short lifecycle and strong will to grow, it’s far easier to create new cultivars of annuals than it is perennials, so there are all sorts of fabulous varieties that combine striking good looks with easy-grow habits.

All these stunning flowers for backyard color are here for a good time, not a long time, but are they worth growing for just one summer of joy? Absolutely. Firstly, these plants are so keen to grow that you can start seeds off in the ground where they’re to grow so it takes very little effort to add them to your garden.

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Secondly, their short-lived nature means they do a great job of filling out gaps between bigger perennials. Whether you’re waiting for perennials to mature to their full size, or you’ve got late-flowering plants that won’t bulk up till summer, these speedy annuals will fill border gaps, fast.

Thirdly, they’ll bring abundant flowers, just as long as you keep deadheading them. Because their life mission is to set seed, as long as you remove faded flowers to stop seed production, the plant will keep growing fresh blooms till fall. And that’s a lot of flowers for the price of a packet of seeds.

Most of these beauties will happily self-seed so you’ll have flowers forever more, or you can collect and save the seed in fall, to sow again next year.

So, stockpile seed packets now and sow outside as soon as you’ve passed your last frost date, depending on your USDA zone. All these fast-blooming beauties can be started indoors, too, then hardened off and transplanted outside once the warm weather is reliably here. Just be sure to use biodegradable pots so you can put your young plants into the ground, pots and all, without disturbing their roots. Lots of gardeners do both, sowing seeds in the ground but also starting a few indoors as an insurance policy in case there’s an unexpected late frost.

This has the added benefit of being able to recognise the young leaves so you don’t accidentally pull out those you’ve direct sown, mistaking them for weeds.

Here's my pick of striking annuals to direct-sow for showstopper flowers that fill your border gaps, fast. Which are best to brighten up your backyard?

1. Cosmos

The feathery foliage of cosmos is as pretty as the flowers, and just wait till you see how many blooms one plant can produce! Super-easy to grow from seed and requiring very little care, cosmos do best in a sunny spot with well-draining soil. When your seedlings have three or four pairs of true leaves, pinch out the top growing tips with your index finger and thumb to encourage the plants to branch for lots more blooms.

2. Poppy

Every garden needs some Papaver petals, and poppies will grow pretty much anywhere, though they prefer a sunny spot with well-drained soil. The tiny seeds need light to germinate so it’s best to rake the soil, water then scatter the seeds onto the surface – and that’s it! The shapely seedpods last for months once flowers fade.

3. Zinnia

Few flowers are as easy to grow from seed as zinnia, taking just three months to bloom. Native to South Western US and Mexico, zinnias are sun-lovers and need warmth to grow well, so wait until the weather has reliably warmed up before sowing in your sunniest spots. Before plants reach a foot high, pinch out the main growing tip to force multiple stems for lots more flowers. Most modern cultivars don’t grow true from the seed they produce so, rather than collecting seed from your plants to sow again next year, it’s best to buy new seed.

4. Love-in-a-Mist

Nigella brings not just pretty blooms on half-meter stems, but fabulous seedpods that look like they come from outer space! Leave some over winter as ladybugs love to hibernate in them. Sow sun-loving love-in-a-mist where it’s to flower as it doesn’t take well to being transplanted, and you’ll have abundant blooms in 2–3 months.

5. China Aster

Another sun-lover, Callistephus chinensis flowers in late summer just as many other garden blooms are fading. They don’t tolerate cold conditions so sow these in late spring once the soil has warmed and all danger of frost has passed. China asters typically take four months from sowing to flowering and, if you keep snipping off faded blooms, will continue flowering into fall until the first frost.

6. Cornflower

Typically germinating in a week and flowering in 2½ months, Centaurea is super-easy to raise from seed and fairly cold-tolerant so you can chance an early sowing. As long as you keep snipping faded blooms from sun-loving bachelor buttons, the plants will flower all through summer, and it readily self-seeds for another show the following year.

7. Calendula

These sunny delights are often grown in veggie gardens to attract pollinators, but Calendula deserve a place in ornamental borders too. As long as you keep deadheading, they’ll bloom for months and if plants start flagging, a treat of tomato feed every couple of weeks will refuel this fabulous flower show till September. Although it’s an annual, calendula tolerates some cold so is worth sowing early.