Sow biennial flowers as the blooms of this year’s display start to fade, so you can be sure you’ll have that dazzling colour back again next year.
Spring-flowering biennials like wallflowers, bellis, forget-me-nots and sweet williams are great value in the garden as they burst into flower early in the season, making them fabulous partners for tulips and daffodils. They have a two-year lifespan, spending their first year developing a nice healthy crown of leaves before blooming in their second year.
Find an out-of-the-way corner of the garden and prepare the ground well, digging it over and breaking it up with a fork then raking it into the texture of fine breadcrumbs so it’s easy for tiny seedlings to push through. Make shallow drills with a cane, about 15cm (6”) apart, and water along the bottom before sowing to make sure your seeds go into the damp soil.
Sow seeds thinly along the row and cover lightly with dry soil, remembering to label each row. In a few weeks, the seedlings will be up and jostle for position. Thin them out gradually as they grow, pulling out any weak seedlings to leave the strongest plenty of room to grow.
Then in autumn, carefully dig up each young plant with as much root intact as possible and transplant them into their final positions; if you do this at bulb-planting time you can plant both at the same time, coordinating your displays to perfection.
You’ll find an exciting range of seed on sale now with dozens of different varieties to choose from, so drop into the garden centre here in London and have a browse. Or you can always wait till next spring and pick up our ready-grown bare-root wallflowers as well as potted sweet Williams and forget-me-nots to drop straight into the garden for a riot of spring colour.