Bridging the Gap with Biennials

I have extended my cutting patch this year, adding two new raised beds.  I got a little bit overexcited by my new space and went on a spending spree with the marvellous Chiltern Seeds.

You might have thought that two varieties each of Cosmos, Zinnia, Scabious, Nicotiana and Nigella might be enough to sate my appetite for seed-sowing.

Greed goes hand in hand with gardening.  I visited Great Dixter at tulip time, and entered a state of ecstasy over the wonderful tapestry of Honesty, Smyrnium and Wallflowers which stitch together the spring display.  I had to have some of that rich abundance so early on in the year.

So, here I am with my newest collection of seed packets.  The biennials.

In case you are new to gardening, here is a quick guide to annuals, biennials and perennials.

Annuals are plants which you grow from seed in early spring.  They produce a profusion of flowers from midsummer until the first frosts.  They flower themselves to death (creative types).  If you let them, they set seed in that time (you can collect this for next year), thus ensuring the next generation of plants.

Biennials are sown in summer.  They put on root and foliage growth into autumn.  You plant them out, and they go quiet over winter.  But then they spring into action when the days start getting longer, ready to produce flowers in April and May.  This timing is really useful, as these are the months when there can be a gap in the cutting patch’s production, before the annuals have kicked in.

Perennials are plants which live for more than two years.  Some perennials are short-lived (three to five years) and some are long-lived (five to ten or even twenty years).  Peonies are one of the longest-lived perennials, often seeing fifty years old.

Now, I already grow masses of forget-me-nots (Myosotis sylvatica).

Myosotis (forget-me-nots)
Myosotis sylvatica (forget-me-nots)

They were given to me as single plants, and have subsequently produced enough seed to populate a small country.

Forget-me-nots are fabulous for growing in narrow, dry and shady places: all the awkward places where most perennials tend to sulk.  I grow them up two beds along the side of our front path, where they provide a lovely nest for early spring bulbs like Scilla and Narcissus, and then for the tulips.

Then they are accompanied by other ground-cover plants, like purple Aubretia and orange Helianthemum.

By mid-June, the forget-me-nots are getting a little bit exhausted, so I yank them out.  If this sounds harsh, don’t worry.  The yanking rattles their seed-heads enough to disperse gazillions of tiny seed, and within a week I have new seedlings of forget-me-nots plumping up for next year.  These look lovely for the rest of the summer with Alchemilla mollis, Geranium himalayense ‘Gravetye’ and Lychnis coronaria.

Forget-me-nots are the easiest of biennials.  As long as you have some bare soil, you can probably get away with raking it a bit, scattering seed on the surface, and within a couple of weeks you will have a little collection of seedlings.  You can just leave them to do their thing until next April, when they will reward you with clouds of tiny blue flowers.  I can’t recommend them enough.  They are the featured photo of this post, photographed at Great Dixter, with the tulip ‘Abu Hassan’.

My second recommendation is foxgloves (Digitalis purpurea).  These are poisonous if eaten, so exercise caution, but I have always grown them in a garden with small children and dogs, with no ill effects.  I put them slightly out of reach, behind some roses.  You know your children – mine were not flower-eaters, so we were fine.

Foxgloves fill me with nostalgia.  My favourite Beatrix Potter story was poor Jemima Puddleduck, and I cannot see a foxglove without thinking of her tumbledown hovel, with the whiskery gentleman lurking outside.  Foxgloves are perfect for edges: near fences or walls, where the garden meets the wild.  There is a dangerous thrill to a foxglove.  The bees think so too.  That is another thing about biennials.  They provide vital food for the bumblebees, butterflies and other lovely beetles and bugs.

I am looking to diversify from the customary pinky-magenta foxglove.  I am going to add a ‘Dalmation Peach’ to my collection.  Who wouldn’t want a plant called ‘Dalmation Peach’?  I am going to add it to my rose garden, where it can tumble in cottagey profusion with geraniums and lupins and phlox.  It will look particularly ravishing with my darker plum-purple roses, like ‘Tuscany Superb’ and ‘Munstead Wood’.

Next up, is a new love, Honesty (Lunaria annua).  This seduced me at Dixter and Sarah Raven’s Perch Hill.  Look:

Honesty (Lunaria annua) with Tulipa ‘Slawa’ at Perch Hill

Honesty, like forget-me-nots and foxgloves, will self-sow.  I love it when I spot a stray whilst driving along country lanes.  They give a wonderful pop of purple amongst the lime green foliage at this time of year.  The tendency to self-sow makes biennials the lowest-maintenance garden plants there are.  They are even able to select the very best spots for themselves, tucking in to places you would never have thought to put them: cracks in walls, nestled at the feet of shrubs, leaning cheekily out from the gatepost.  They are charm itself.

Another new one is Alexanders (Smyrnium perfolatum).  This plant has a lovely association.  They give a sense of wild abandon early on in spring, way before the cow parsley froths up.  They are fabulous zingy green, with sculptural presence, like great heads of artichokes.  Here is the garden version, frolicking with the tulips at Dixter:

Smyrnium perfoliatum (Perfoliate Alexanders) with Tulipa ‘Abu Hassan’ and Hellebores at Great Dixter

Do you see why I love biennials?  With no biennials at this time of year, the tulips would be surrounded by patches of bare soil, with a few mounds of foliage from the emerging perennials.  The biennials provide this sense of prodigious growth, filling out the border with both plumped-up foliage and carefree sprays of flowers, until it is fit to burst.

I think we have room for one more biennial, the humble Wallflower (Erysimum cheiri).  Confusingly, there are the classic biennial wallflowers, but there are also some short-lived perennial wallflowers.  My favourite perennial wallflowers are ‘Bowles Mauve’ and ‘Apricot Twist’.  They flower for nearly all of the year, but are expensive, and tend to lightly flower the first year, are magnificent the second and third, and then go all woody and keel over the fourth.  They are also expensive.  Biennial wallflowers however are cheap as chips to raise from seed, and so can be grown en masse.  Here they are providing rivers of colour in the Cottage Garden at Sissinghurst:

Erysimum cheiri ‘Fire King’, ‘Blood Red’ and ‘Cloth of Gold’ with Tulipa ‘Aladdin’

Whilst biennial wallflowers tend to be associated with these hot colours, I am going to mix things up a bit, and go for some warm pinks and purples, with ‘Giant Pink’ and ‘Sunset Dark Purple’. They will look just mmm-mmm with some pale pinks and darkest plum tulips in my cutting patch next spring.  They smell rather nice too.

Now for the practical bit.  If you are thinking of following suit and sowing some wonderful biennials to plump up your late-spring to early-summer garden, here is how:

I will sow these biennial seeds in trays in a couple of weeks, using the same techniques as for annuals.   You need multi-purpose compost (let’s not complicate things with seed compost; I have found this to be unnecessary), sprinkle it with water from a can, then a light sowing of seed on top, a sieved sprinkle of compost or vermiculite, and keep it damp until the seeds start to germinate.  These seeds are fine in a sheltered spot outside, but bring them in overnight if a frost is forecast.  Thin the seedlings out if necessary, prick out when there are two pairs of leaves.  This just means levering them out of the tray and into some waiting pots.  Keep them damp but not saturated through the summer.  I will plant them out into their final positions in late summer, for flowering next spring. 

These biennials will self-sow in subsequent years, delighting you with their creativity forever.  Alternatively, if you have a cutting patch, you can grow them in neat little rows or blocks, and cut them for the house to accompany daffodils, tulips, alliums and gladioli.  Keep picking these flowers, and they will just keep on producing until midsummer.  Collect seed and start again!


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29 Comments Add yours

  1. annpappas says:

    I had to give up on Tulips – they are unobtainable here and my brother could send me some from the Netherlands but it would take too long, so I will wait until next year.

    1. Ali says:

      OH, that’s a shame. But you will enjoy them all the more for the wait.

  2. janesmudgeegarden says:

    I sure am tempted! Thanks for all the good info. I just sowed some honesty seeds today, in fact. Probably the wrong time but I thought I’d give it a go. And I love wallflowers so I think I’ll get some of those as well and plant them in early spring.

    1. Ali says:

      I am the queen of giving things a go (ignoring the instructions!)

  3. Must not click on the link to Chiltern Seeds..! ☺ I can’t wait to see photos of the foxgloves, Dalmatian Peach sound dreamy.

    1. Ali says:

      I know the feeling. They do, don’t they? Couldn’t resist.

  4. Foxglove are gorgeous! Such wonderful information. Fire King, blood red, are beautiful. 😊

    1. Ali says:

      They are, aren’t they? Can imagine rather a lovely botanical illustration!!

  5. I’m positively salivating with plant lust after reading this! :~)) And the Chiltern catalogue… I tend to browse it online nowadays, but for many years I’d wait expectantly for it to plop through the door straight after Christmas, and then spend the next fortnight reading it, cover to cover.

    1. Ali says:

      It is a thing of beauty. Mine is looking a bit dog-eared now because I have leafed through it so many times!

  6. FlowerAlley says:

    This is great. Thanks

    1. Ali says:

      It’s my pleasure!

  7. bcparkison says:

    A dream garden. Why have I never had any Forget- Me- Nots? Love all the photos

    1. Ali says:

      I got into them by accident. My mum’s garden had them everywhere and they were just so lovely that I borrowed a few!

  8. Thanks for the reminder to get some new wallflowers. Mine stopped coming up a couple of years ago. I too have a large (and getting larger all the time) forget-me-not patch mixed in with irises and many other flowers. I love how they reseed so easily and attract all kinds of bees and other pollinators. When they get tired looking I too yank them out. I also just sowed a big corner with wildflower seeds which are sprouting up from the ground. Happy Gardening!

    1. Ali says:

      Yes, wallflowers do get a bit straggly over time and need a helping hand where the forget-me-nots and foxgloves look after themselves. And you’re right, it’s the beneficial insects that make these all worth growing.

  9. Heyjude says:

    A very informative post. I have bookmarked this for reference. I have some wallflowers flowering that I don’t recall planting, they must have been part of a bee-friendly packet of seeds I scattered last June. I have also spotted some Honesty down the lane and will be looking out for the seeds later on so I can grab some and give them a go. I do like Honesty and the paper ‘money’ discs. Can I fit some foxgloves in? Well it seems I may have one of those in the veggie bed already. I imagine it is the common purple one as they grown in the lanes, but I am happy to see it. ‘Dalmatian Peach’ conjures up a very spotty pale peach combo. I tried seeds of ‘Suttons Apricot’ but nothing appeared

    1. Ali says:

      Fab. If you leave your foxglove it will self-seed, I bet. Yes, not sure if ‘Dalmatian Peach’ will be as vigorous and resilient as Digitalis purpurea. It may revert back to species when self-seeding too, of course!

      1. Heyjude says:

        Oh, well, we shall have to wait and see. The fun of gardening 😀

  10. pommepal says:

    Am I tempted? Am I ever… I just drooled over all your delicious descriptions of colour combos and delightful plants. I feel like pulling out all my tropicals and starting again. But sadly I have been there done that when I first moved here from NZ, where I had a beautiful cottage garden filled with all those gorgeous plants, but they do not like this climate, there is nothing sadder than a wilting foxglove, sparcely struggling snapdragons and disease invested roses. So now I go with the flow and just put in the plants that thrive in this heat and humidity. But I love drooling over your photos an inspiring dialogue, keep them coming

    1. Ali says:

      That reminds me that I planted hydrangeas in a garden in the edge of the bush. You can imagine how that went! 😂 Much better to go with what thrives.

    2. Ali says:

      And thank you for the lovely comment.

  11. Emma Cownie says:

    Thank you for the explanation about annuals etc. I absolutely love your photos.

    1. Ali says:

      I’m glad you enjoyed them, Emma.

  12. Chloris says:

    I went mad on seeds this year, ( even more than usual) It’ s all very well when you have the excitement of germination and dear little seedlings but then it gets out of hand when they all need pricking out. And then where do you put them all? Help, what was I thinking? Sheer greed.

  13. Sam says:

    I’ve totally cut back on seed sowing this year – I can’t bear the guilt of all those seedlings that need pricking out and potting on and keeping an eye on when I just don’t have the time to do it! Next year… In the meantime, I’ve bought some foxglove plants for the newly cleared areas so they can do their own self-seeding. You can never have too many forget-me-nots in my opinion 🙂 I had to smile at your reference to Alexanders. I live in that very place (we may have walked past each other) and the verges, hedgerows and margins are heaving with the stuff right now.

    1. Ali says:

      What a beautiful place to live! I love it that way. And I love easy self-sowing plants too.

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