5 tips for adding biennials to your garden

Whether you're working with hardy annuals, short-lived perennials or true biennials, starting flowers in late summer to bloom the following spring often seems like a form of green magic. But it's easier than you might think. Here are five tips for adding gorgeous biennials to virtually any garden.

Annual flowers grow for only one year, while perennials keep coming back season after season. In between there are biennials. So what exactly are they?

• Biennials are plants that sprout from seeds and produce leaves their first year, then bloom, set seed and die in their second year.
• True biennials are rare in nature, but many garden flowers behave like biennials, depending on the climate.

The time to plant biennials is important to know (and follow), ensuring their growing success.

• Plant biennial seeds in pots or prepared beds in late summer.
• If you live in a colder climate, plant them outdoors in the fall at least six weeks before the first frost or overwinter them in a cold frame.

Above all, don't keep the plants indoors all winter.

• They need a good winter chilling to trigger heavy spring blooming.

Biennials can also fill the colour gap between spring-flowering bulbs and early annuals and perennials.

• In early fall, plant low-growing biennials among spring-flowering bulbs.
• Plant the bulbs first, then interplant them with biennials.
• The bulbs will pop up and bloom first, and the biennials will help hide their ripening foliage from view.

Many biennials are big seed producers and will shed so many seeds that volunteer seedlings pop up year after year.

• To help, let some flowers mature until they turn brown.
• In late summer, weed and water the area to give seedlings ideal conditions to sprout.

The money plant (also known as silver dollar plant) is a true biennial prized for its flat seed pods, which make great additions to dried flower arrangements.

• After the seed pods have dried out completely, rub the flat disks lightly between your fingers to remove the brown outer membranes.
• With luck and a bit of practice, the bright, silvery central membrane will be left intact for you to use in winter floral displays.

These are among the most popular choices of flowers you could add to your garden and handle as biennials. Your local garden centre or home improvement store can help you pick plant varieties that will do well in your area.

• Canterbury bells (Campanula)
• English daisy (Bellis perennis)
• Foxglove (Digitalis purpurea)
• Hollyhock (Alcea rosea)
• Money plant (Lunaria)
• Pansy (Viola x wittrockiana)
• Siberian wallflower (Cherianthus allonii)
• Stock (Matthiola maritima)
• Sweet William (Dianthus barbatus)