‘Best’ flowers to plant in March to have big, colourful summer blooms

Half hardy annuals

Unlike hardy annuals, half hardy annuals sown in March should be grown under cover, as they’ll die in the frost. You can plant them outside after there’s no longer a risk of frost.

Dahlias

The beautiful, spiky flower will bloom in its first year if grown in a greenhouse in March. BBC Gardeners’ World said dahlias need moist compost to grow.

Fast growing perennials

The colourful flowers can be grown in spring, but under a cover. Sow them indoors under glass, then remove the cover when the seedlings have appeared.