Whoever came up with the phrase ‘good things come to those who wait’ was probably a gardener. Sometimes the wait is relatively short. Annuals go from seed to a bouquet of flowers in just a matter of weeks. Biennials, on the other hand, have longer term plans. Sow them in June or July and they will germinate and get nicely established in their first year. Next spring or early summer, with strong roots and a good set of leaves, they start producing flowers in profusion.
Why grow biennials?
If you’re after flowers to feed pollinators or to cut and enjoy in the house, you could just grow those fast-living annuals. Many of them will keep on producing blooms for weeks on end, as long as you deadhead and feed them. But then you and your garden will be missing out on the tall spikes of foxgloves, the evening scent of sweet rocket, and the quirky seedpods of honesty. Plus, a lot of biennials will be flowering well before the spring sown annuals are even thinking about producing buds.
And, of course, bees and other pollinators love biennial flowers just as much as any other nectar-rich blooms.
How to grow biennials
Sow biennials in June or July for flowers the following year. Start them in modules or pots… you can sow direct, but who has space in the border in June? Fill your modules with a good peat-free compost, water gently and add one or two seeds per module. Cover with a light layer of compost or vermiculite… except foxglove seeds, they need light to germinate. And while we’re talking about foxglove seeds – they’re really small, like dust small. I heard Sarah Raven and Arthur Parkinson on their podcast recommending sowing foxgloves into seed trays rather than modules. Take a tiny pinch of seeds and scatter them quickly and evenly over the surface of the compost. I tried this and it did seem to work, and saved a lot of faffing about with trying to sow just one or two seeds into each module.
Transplant the sturdy seedlings to their flowering positions in early autumn – once the annuals have done their stuff and are ready to make space. Don’t forget to water after planting, and again as needed if the weather is dry.
angelica (honey bees, bumblebees and wasps love the flowers), foxgloves, teasel (also produces seeds for birds), hollyhocks (a short-lived perennial but best treated as a biennial)
Cut flowers –
wallflowers (great with tulips for spring flowers), sweet rocket (the flowers are pretty and edible), sweet William, honesty
angelica (plant towards the back of the border… it gets very big), foxgloves (plant them with alliums for a striking early summer display)