6 hardy annuals to sow in April before it's too late, including beautiful cornflowers
These easy-to-grow annuals will reward you with weeks of colour
April is one of the most generous months in the gardening calendar, offering ideal conditions for sowing seeds that will carry your garden through summer.
"It's the perfect time to start sowing hardy annuals that bring quick colour and busy borders with very little fuss," says Eve Kerrigan, Content Creator at British Garden Centres. Whether you're sowing directly outdoors or starting seeds under cover, this is the moment to get going.
"As a starting point, I begin to sow hardy annuals under cover in seed trays filled with peat-free compost," Sarah Raven previously told Country Living. "Place them in a spot that receives good light and choose reliable varieties like cosmos, ammi, and marigolds for best success."
With a little care now, you'll be rewarded with a long season of colour. Take a look at the hardy annuals to sow now before it's too late...
Cosmos
Light, airy and endlessly elegant, cosmos are a firm summer favourite for many.
"As a starting point, I begin to sow hardy annuals under cover… choose reliable varieties like cosmos… for best success," explains Sarah.
Top tip: Best started indoors or on a bright windowsill, they can be planted out once the soil warms, bringing months of soft, fluttering blooms.
Cornflowers
A cottage garden classic, cornflowers bring vibrant colour and a relaxed feel.
"Flowers like cornflowers can be sown directly into borders or pots, and they’ll reward gardeners with weeks of colour from early summer onwards," adds Eve.
Top tip: They’re ideal for filling gaps in borders and are loved by pollinators.
Sunflowers
Few flowers make an impact quite like sunflowers. "They are one of the easiest and most rewarding annuals to sow in April," says Ezgi Sumen, manager at Plant Warehouse.
Top tip: Choose dwarf varieties for pots or taller types for borders, and sow directly outdoors as the soil warms.
Zinnias
If you’re after bold, long-lasting colour, zinnias are a brilliant choice. "Zinnias flower for months with very little fuss," Ezgi says.
Top Tips: Start them indoors in April and plant out once temperatures rise.
Sweet peas
Fragrant and romantic, sweet peas are a spring staple."If you haven't sown sweet peas yet, April is still a great time," she continues.
Top tip: They love a sunny position and benefit from support, with regular picking encouraging more blooms.
Cerinthe major ‘Purpurascens’
For something a little different, cerinthe offers striking, dusky tones.
"Great varieties include Cerinthe major ‘Purpurascens’ – with its shrimp-like, dark purple-blue flowers," says Nick Hamilton, owner of Barnsdale Gardens.
Top tip: It works beautifully in borders or containers and will thrive in most soils in full sun – allow plants to gently seed before cutting back.
11 fragrant flowers for a scented small garden
What to do — and not do — if you find a baby bird
Chelsea Flower Show 2026: Who are the presenters?
3 fast-spreading plants to grow now
