Home Propagation Biennials


Growing biennials from seed

Many people don’t bother with biennials and that’s a shame. True, in a small garden, sowing flowers that aren’t going to bloom until the following year can seem a waste of space.

Sweet rocket
Sweet rocket – both the white form and the lilac one hiding in the background

However, these are the plants that fill that awkward flowering gap between late March and the end of May (or beginning of June here) – wallflowers, foxgloves, sweet William, honesty, sweet rocket, perennial stock and Icelandic poppies.

In my garden, foxgloves and sweet rocket seed themselves after flowering – I just move the ones that are in inconvenient places.

It really needn’t take up much room to grow from seed – sow from May-July – give them a go for floral delights next spring.

  • SWEET WILLIAM (Dianthus barbatus): The epitome of the cottage garden – and lovely scent too.
  • SWEET ROCKET (Hesperis matronalis): Another serial self-seeder – I didn’t even introduce this one! Both the mauve and white varieties appear at the end of May through June. It’s very happy in partial shade.
  • HONESTY (Lunaria): Similar in flower to sweet rocket, but earlier, and in white and purple. It’s the seed pods people adore – paper moons.
  • PERENNIAL STOCK OR BROMPTON STOCK (Matthiola incana): Confusing name, because it can survive into a third season, with an old clove carnation scent, flowering from April until late June. Many colours and forms.
  • ICELAND POPPIES (Papaver nudicaule): Lightly scented, crumpled silk-like petals, deeper coloured towards the centre, gold anthers.

Spring fragrance – wallflowers

Wallflowers (Erysimum) are a lovely, beautifully fragrant spring flower.

I grew them a few years ago – Fire King (deep red) and Cloth of Gold (funnily enough, gold) – sown in a couple of rows in a gap in one of the raised beds.

When the seedlings were big enough to handle, I potted them up into yoghurt pots, then moved them to their final positions after the annuals were finished in October. Pinch out the growing tips for bushier plants.

Plant World Seeds sells a lovely mixture of its own, Plant World Rainbows, well worth investigating – in fact, there’s several great packets-worth there.

They’re one the most reliable spring bedding plants, surviving frosts and harsh winters. The flowers vary in colour between yellows, reds, oranges and pinks, growing to 20-40cm high.

Foxgloves – perfect for shade

Foxgloves (Digitalis) are one of my favourite flowers – what’s not to love about a plant that looks after itself, has gorgeous blooms and likes shade?

My original garden stock came from one 99p packet of rare mixed seeds (some of them are perennial).

The general rule is, the shorter they are, the more likely they’ll be perennial.

I let them self-seed – there’s the native purple foxglove, the white variety (both the most rampant self-seeders), plus apricot (no offspring), ones with deeply-freckled throats and there was a pink/purple giant over 6ft tall.

They have been added to by some Dalmatian Mixed (a cheapo plug plant mix), plus Summer King and Candy Mountain.