Sowing Biennials

Hesperis-MatronalisWhat are Biennials?

Biennials are hardy plants which grow roots and foliage this year then flower next year. Sown in summer they have around eight months to produce super strong healthy plants which are capable of producing lots of lovely strong flower stems from late spring onwards.

Why grow Biennials? Biennials are brilliant for early flowers next year. They usually start blooming in May and finish in July although there are exceptions. A patch of Hesperis (Sweet Rocket) in our garden has been flowering since April and is still producing lovely pale purple blooms in August. If you like to grow flowers for your home or you have a special event in late spring or maybe you are planning to sell cut flowers next year…  you’ll find biennials very reliable and super productive. They are inexpensive to grow from seed, healthy and vigorous and more to the point don’t need much attention from the gardener.
What’s not to love?

Biennials-VaseBiennials are ideal for filling the colour gap in late spring. You know that green period when the most of your spring bulbs have finished blooming and just before your perennials get underway? That’s when biennials come into their own! Each year I spot some gaps in our garden and I kick myself for not growing more. Some years I’d kick myself in the head if I could! So I’ve made up my mind that in 2017 it’s going to be different. We’re growing lots of Biennials!

Summer is the ideal time to sow Biennial Seeds. We have a spare patch of ground (slightly shaded but it will do the job)  so I’ve prepared a seedbed for them. I spread the preparation over three days… just twenty minutes each day… to get it just right. The main advantage to taking your time with ground preparation is that the soil will start to dry out a little so it becomes lighter and easier to work On day one I dug the ground and removed weeds and most roots leaving the earth in huge clods. On day two I used a fork to break the clods into smaller lumps. On day three I raked the earth to a fine tilth. If you prefer you can get the job done in one go but I like to tackle things in twenty minute chunks… mainly to stop me losing the will to live! Anyway, the aim is to produce a fine crumbly texture which tiny seedlings can push their way through. You can see how the bed changes over three days. Seeds sown into the ground at stage 1 and stage 2 would have no chance of pushing the earth aside with their tiny shoots.


Foxglove SeedingsToday I’m sowing my biennials directly into the soil. Here in our Lancashire garden they will have enough time to develop into nice healthy young plants before the weather changes in October. As usual I have also sown some seeds indoors in modules. It’s not always necessary but I like to hedge my bets just in case the seeds outdoors are eaten or washed away. Tiny seeds such as Foxgloves benefit from a little tender loving care indoors and I like to know that I’m guaranteed lots of lovely plants for late spring. I find it’s best to use a small module tray and sow just a few seeds into each cell then if one cell damps off the other seedlings won’t be affected.

You’ll find a more detailed guide to growing Foxgloves on the Resources page


I love Foxgloves but they aren’t the only Biennials I’m growing for spring. This month I’m sowing:

  • Dianthus barbatus (Sweet William) which has lovely long strong stems and clusters of colourful blooms,
  • Eryngium giganteum (a short lived perennial I treat as a biennial)
  • Aquilegia vulgaris (a short lived perennial I treat as a biennial)
  • Lunaria annua (Honesty) which comes in white and shades of purple,
  • Papaver nudicaule (Iceland Poppies) and of course
  • Hesperis matronalis (Sweet Rocket)

Biennials Collage

Hesperis-Collage-500    Digitalis-purpurea-Collage-500    Mixed-Honesty-Collage-500

Love GillianJust in case you were wondering… YES! They are available in my online shop. As you know I only sell seed for those plants I grow and recommend so you can be sure that these particular varieties are super-duper.

Are you growing Biennials this year? I’d love to know which varieties you grow in your garden and which do well for you.
Today I’m joining in with Cathy at Rambling in the Garden. I’m showing blooms from late spring rather than a bunch picked today… even so I do hope you like the flowers!
Hope you are having a lovely sunny Monday. Happy Gardening! Gillian 🙂

20 thoughts on “Sowing Biennials

    1. Oh Yes Lisa! It’s frustrating in spring when I have gaps in the garden too. This way I’ll have plenty of blooms for cutting AND a nice colourful garden.

  1. A lovely vase, Foxgloves are a very early spring flower where I am from and to see them in July is amazing! They won’t grow here in Florida – my biennial is Beach Sunflower!

    1. They do like a semi shaded spot so I’m guessing that Florida is waaaay to hot for Foxgloves. This vase is from earlier this year but last year our Foxgloves flowered twice. Once in spring and then again in autumn. I’m glad I didn’t rip them out as soon as they had finished flowering.

    1. Thanks Kate. I love my little seed shop! I’m slowly adding the best plants to it so feel free to suggest any seeds that you’ve had good results with… I know that you have plenty of experience producing plants for your own lovely garden and I would appreciate your thoughts.

  2. Yes, I plan to do exactly the same – the gaps should avoidable! Are those yellow aquilegia in your very pretty ‘country garden’ vase? I still have some yellow/orange ones flowering whereas the others finished weeks ago. A really interesting post, Gillian, so thanks for sharing

    1. Good for you Cathy! You can never have too many biennials! Well spotted… that is Aquilegia you can see. I grew them from seed again and was delighted with the results. Lots of lovely soft yellow and gorgeous pinks and white too all with long spurs. Thanks for hosting. Will try harder to remember before I write the post that I need to prepare a vase next time!

  3. You make a good case, Gillian! Regrettably, seeds and seedlings tend to be overrun by raccoons in their never-ending search for grubs in my garden.

    1. What a nice problem to have! I’ve only ever seen raccoons on the telly. You are very lucky to have them in your garden Kris.

  4. I was worried I’d left it too late but I think that here in Italy it may still be a little early; it is still so hot!!

    1. Too hot sounds like too early to me too! Biennials need time to establish themselves before winter sets in so you’ve probably got ages yet Christina. Not to hot here today. It’s quite windy and fresh… jumper weather I’d say!

    1. You still have time Joanna, especially if October is lovely and mild like last year. Well worth doing if you like lots of plants without breaking the bank!

  5. A really helpful post. Not only did I love the beautiful arrangement in the white jug but I also couldn’t help noticing how beautiful your soil is. I thought it was potting soil at first because it is so dark. Florida soils are basically sand – no matter how much organic matter I dig in I don’t think they could ever look as good as that!

    1. Thanks Kate. Our soil is actually clay but we improve it with lots of homemade compost. Sandy soils have advantages though… not so hard to dig!

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