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10 vibrant flowers to plant in May for a summer garden full for colour, including sunflowers
Garden experts share their best-loved blooms for low-maintenance summer planting
There are numerous things you can add to your garden in May for flower-filled borders all summer long, including varieties that can be planted directly in the soil.
You can sow seeds, then share your plants around if you end up with too many, or take the easy option and buy young plants from the garden centre that can be popped straight into the ground to give flowerbeds an instant lift.
"Every year we grow lots of easy annuals outside in May," says expert gardener Iben Lund Gladman of seed specialists Stocks & Green.
"Although many annuals can be started inside earlier, those sown outside later often catch up as the light levels are now good, and many prefer not to be disturbed at the pricking-out stage.
"It's worth mixing tiny seeds with sand to help with the sowing. Try sowing in wavy lines, which looks more natural but still enables you to spot the seedlings."
Below, discover 10 kaleidoscopic varieties you can plant outside now for a summer garden full of colour and life.
Chinese aster
Jane Westoby, creative director of The Hampshire Seed Company, calls China asters a "brilliant choice" for May.
Sow them now and you’ll be harvesting armfuls of these delicate-looking but surprisingly resilient flowers when other blooms in the garden are winding down.
California poppy
"California poppies are ideal for hot, sunny, free-draining spots where you want colour without much fuss," says horticultural specialist Patrick Martin.
This orange cousin of the common poppy flowers in 6 to 8 weeks. Choose a spot in full sun and avoid overwatering; this flower is drought-tolerant once established.
Cornflower
This classic cottage garden favourite flowers in 8 to 10 weeks and is a boon to bees and butterflies. Grow them in full sun in moderate to well-drained soil. Wildflowers being naturally hardy, so blue beauties don't need much in terms of care and maintenance, so water only sparingly.
Cosmos
May is also an excellent time to grow cosmos. Plant them now, and they'll fill your garden with colour all summer long.
"They are great to grow in containers, but avoid small pots as you will be watering constantly," advises Iben. "Don't forget a really good drench is the best way to water and ideally add a good layer of mulch."
Foxglove
Jane says that May is the perfect time to sow foxgloves, too. Although they flower the year after being sown, it’s well worth the wait.
Nasturtium
There is more than one reason to plant these orange blooms now. "Nasturtiums are perfect gap-fillers, the flowers and leaves are edible, and they actually prefer poorer soil compared with a lot of bedding plants," says Patrick.
Plant them in full sun to light shade in free-draining soil, where they will establish in just 6 to 8 weeks. An extra tip? Plant them next to your vegetables as a sacrificial plant for caterpillars and other pests.
Sunflower
Now is also an ideal time to start planting your sunflower seeds, although be aware that it takes multiple months for them to grow.
"For instant impact, dwarf sunflowers like Teddy Bear or Music Box are quick and cheerful, and the seedheads help wildlife later on," Patrick shares.
Nigella
Iben recommends Nigella damascena ‘Miss Jekyll’, the classic love-in-a-mist flower that’s easy to grow and loved by pollinators. You can also try Calendula ‘Sherbet Fizz’, a beautiful pastel-coloured marigold for a softer, subtler look to the traditional bright orange.
"They’re good for bees, and they also give you those decorative seedheads and often self-seeds for next year," adds Patrick.
Pot marigold
"Calendula, or pot marigold, is a safe bet in May because it’ll put up with cooler nights and still gets into flower quickly," says Patrick.
This bright bloom flowers in about 6 to 8 weeks, is reliable for early colour and keeps going if picked regularly. Grow calendula in full sun or light shade, in average, well-drained soil. Water moderately and deadhead regularly to keep it flowering.
Zinnia
"If you’re looking to inject vibrant, long-lasting colour into your garden, zinnias are a must-sow in May," says Jane. "These hardworking annuals thrive in the warmth and are true cut-and-come-again stars – the more you harvest, the more they bloom."
Sow them now and you can enjoy their soft pastels and jewel-toned pinks in as little as 6 to 8 weeks. Once established, they bloom all summer long and into early autumn.
Wanda Sachs is the Multiplatform Writer for Country Living and House Beautiful, exploring the latest in gardening, wildlife and sustainable living alongside interiors and property. She is particularly interested in human-interest stories, the intersection of design and pop culture, and the evolving relationship between urban and rural life. Previously, she served as Associate Editor at The Berliner in Berlin, where she reported on culture and fashion. Wanda studied English and German at the Goethe University Frankfurt and Exeter University.
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