What Are Biennials? Best Biennial Flowers to Sow Now for colourful blooms next year

What are biennial flowers?

Biennial plants are sown in their first year and bloom in their second. Sow these varieties now for vibrant flowers in spring and early summer next year, before annuals start into flower.

Last June Suburban Sue posted about some self-sown varieties in her garden  sow biennials in June ready to flower next spring  

How to grow biennial flowers

Choose a sunny sheltered site to sow seeds outdoors where you want them to flower. Remove any weeds and rake the surface level. Either 'broadcast' ie sprinkle across the surface and cover with soil or make shallow channels for sowing the seeds, spacing to instructions on the packet. 

TOP TIP: Water the soil BEFORE sowing your seeds and covering with soil.

Or you could start the seeds in trays indoors, on a windowsill or in a greenhouse. Prick out into individual pots when the seedlings are big enough to handle, harden off and grow on in a sheltered spot outside. Plant into the final positions and water in dry spells. 

Popular biennials/short lived perennials to sow now:

Dianthus barbatus / Sweet William

Perfect for cutting, in beautiful shades of red, pink or white. Relished by pollinators, these fragrant blooms thrive in sunny spots, reaching 60cm tall. 

Lunaria annua /Honesty

Suitable for sun or partial shade, these purple or white flowers produce papery seedheads for dried floral arrangements. Another flower loved by pollinators, it self-seeds freely, reaching height of 60cm

Matthiola incana / Cinderella

A superb mix, for richly scented blooms in shades of pink, mauve, red and white. Suitable for both borders and pots, as a cut flower they stay fresh in the vase. 

Digitalis Dalmatian/ Foxglove

For dappled shade, these tall spikes of mottled pink, white, purple and peach are popular with bees. Foxglove self-seeds readily but needs light to germinate so don't cover. Good in borders, the hybrids produce compact branching plants, height 80-110cm. 

Hesperis matronalis/Sweet Rocket

The most sweet-smelling fragrant flowers in the evening, in pink, purple, mauve or white. A favourite for butterflies, it grows to a height of 60-90cm. 

Lupin Russell/Lupin

For colourful spikes of flowers in early summer, ranging from white to pink, red, purple, yellow and blue plus combinations in between. These ornamental sun lovers rise to 90cm tall. Beneficial for fixing nitrogen 

Erysimum/Wallflowers

From glowing orange-scarlet flowers through to sulphur yellow these fragrant blooms are sweetly scented. Growing to 30cm.

 Alcea Rosea/Hollyhocks

Statuesque long flowering plants over 2m tall for informal borders. Single flower varieties are best to attract pollinators