Wednesday Weed – Perennial Cornflower

Perennial cornflower (Centaurea montana) in the process of escaping….

Dear Readers, it is always interesting to see a garden plant in the actual  process of escaping from the garden. When I got back from Dorset this week I noticed that a perennial cornflower (Centaurea montana) had seeded itself into the wall of the house opposite. It’s quite possible that the next generation will appear somewhere along the street, as, with council cutbacks, the streets of East Finchley are not being swept and ‘de-weeded’ with quite the enthusiasm of yore, and all sorts of plants are popping up in the debris that is left. It is such a striking plant, and is closely related to the cornflower and to our native knapweed (Centaurea nigra). Perennial cornflower, however, is a plant of southern Europe, particularly the mountain areas – another alternative name is ‘mountain bluet’. No wonder the plant is happy in crevices and exposed spots, and is relatively drought-tolerant. I’ve noticed before how many of our ‘alien’ weeds are originally from mountainous areas, which mimic the harsh conditions of our cities, buddleia being a splendid example. Other plants that were originally from mountainous areas include fox-and-cubs (Pilosella aurantiaca), a bright orange daisy from the Carpathians, and purple toadflax (Linaria purpurea), a delicate purple plant which is very popular with bees and comes originally from the mountains of Sicily.

This may also explain why perennial cornflower is naturalised to a much greater extent in the north east of England than in the south, outside of cities – the climate is cooler, and one thing that the plant can’t stand is being waterlogged, which would rule out some areas in the west.

I love the buds – they look to me as if every sepal is surrounded by little eyelashes. And the colour of the flower is an extraordinary deep lavender-blue, set off by the magenta centre. That deep blue colour originally gave it the name of ‘Great Blue-Bottle’ – it seems to have been introduced to the UK some time in the 16th century, as recorded by the herbalist John Gerard in 1597. He didn’t know quite what to do with it: in its native range, the plant was used as a tea to treat dyspepsia and also as a diuretic. In 1790 the gardener William Curtis wrote that it was a plant that ‘will grow in any soil or situation, some will think too readily‘. The Kew Gardens website describes it as a ‘useful, if somewhat untidy, addition to a herbaceous border‘, which seems a little unkind to me. If you tire of the blue variety, there are also white, pink and mauve cultivars, but as usual my taste tends me towards the original plant. It does feel to me as if it would be lovely in a border with other ‘cottage garden’ plants, such as aquilegia. Do let me know if you’ve been growing it, and what you’ve paired it with.

Photo One from

Centaurea montana ‘Purple Heart’ (Photo One)

Sadly, although perennial cornflower has not become invasive in the UK, it has become a problem in places such as British Columbia in Canada and the Rocky Mountains (where I would expect it to be happy, what with it being a mountain and all). Indeed, if you spot a perennial cornflower in the Pacific Northwest, you can shop it to the authorities by calling the Weeds Hotline. Sometimes, a plant can just make itself way too at home, and as perennial cornflower propagates both by seed and by rhizome it has several ways to spread. It is also believed that ants might feed from the profuse nectar produced by the flowers, and hence accidentally transfer pollen to other plants.

Unfortunately, mountain  habitats are some of the most vulnerable to ‘invaders’, and they are already under stress due to climate change. I can understand why people want to protect what is already there. My local ‘patch’ is urban, and hence such a mish-mash of species and influences that I have the luxury of enjoying plants from all over the world.

Perennial cornflower with forget-me-nots at East Finchley station.

The genus name for perennial cornflower, Centaurea, relates to the belief that the centaur Chiron used cornflowers to treat battle wounds. When I was a child I was fascinated by the animals and half-animals of Greek and Roman mythology, such as Pegasus the winged horse and the centaurs and satyrs. I was a rather lonely little girl, and thought that I’d feel at home with all these strange creatures. I would have been very happy having a centaur as a friend and mentor, and I would have been able to ride into school instead of having to share a car with Judith Barlow who used to encourage her brother to pull my hair (not that I bear grudges of course). Chiron was Achille’s teacher, and so I’d be in interesting company, though Achilles attitude to women could have done with a bit of realignment.

I love how, in the illustration below, Chiron is shown as in full Greek dress with a horse’s back end stuck on as an afterthought.

Chiron the centaur being presented with the infant Achilles to teach (From ‘The Golden Porch – A Book of Greek Fairytales by W. Hutchinson (1914)) (Public Domain)

But, as usual I digress.

The flowers of perennial cornflower are said to be edible, and would certainly add a pop of colour to a salad. They are also a good source of nectar for non-human visitors, such as bumblebees and solitary bees, and feature on the RHS Plants for Pollinators list, which is a useful resource, though of course a perfect pollinator plant in one location might be a dead loss in another. I know that the plants that help bees in my back garden (dusky geranium and bittersweet, for example) would fail in the sun-blasted front garden where the lavender thrives. So much of gardening is trial and error!

And now, for something a little different. The author Maggie Nelson (born 1973), most famous for her memoir ‘The Argonauts’, wrote a series of reflections on the colour blue, called ‘Bluets’. They were written during a period when she was going through a relationship break-up, and also caring for a friend who had been rendered quadriplegic. I find what she has to say both intriguing and challenging.  Here are a few excerpts from ‘Bluets’.

“At a job interview at a university, three men sitting across from me at a table. On my cv it says that I am currently working on a book about the color blue. I have been saying this for years without writing a word. It is, perhaps, my way of making my life feel “in progress” rather than a sleeve of ash falling off a lit cigarette.” 

“Eventually I confess to a friend some details about my weeping—its intensity, its frequency. She says (kindly) that she thinks we sometimes weep in front of a mirror not to inflame self-pity, but because we want to feel witnessed in our despair.” 

“Life is a train of moods like a string of beads and as we pass through them they prove to be many-colored lenses which paint the world their own hue, and each shows only what lies in it’s focus. To find oneself trapped in any one bead, no matter what it’s hue, can be deadly.”

All quotes are from Goodreads. If you want to rush out and buy the book without resorting to Amazon (as I am just about to do), it’s available here. There is a very interesting article about this collection of ‘propositions’ here. And here is a final quote.

“That this blue exists makes my life a remarkable one, just to have seen it. To have seen such beautiful things. To find oneself placed in their midst. Choiceless.” 

Photo Credits

Photo One from



11 thoughts on “Wednesday Weed – Perennial Cornflower

  1. Anne

    This is a ‘Goodread’ indeed! I agree with you about alien plants in urban areas – so many of our alien flowers were brought to this country by avid gardeners. It is when they escape into the wild that they can cause problems for the indigenous vegetation and for stock farmers (some are actually poisonous to animals). I smiled at your comment “with council cutbacks, the streets of East Finchley are not being swept and ‘de-weeded’ with quite the enthusiasm of yore, and all sorts of plants are popping up in the debris that is left.” for in our town the local council seems to have given up: storm drains are choked with weeds and litter and our town is overrun with cattle – at least they munch the grass verges 🙂 We tend to think this lack of attention is only experienced here, but you make it clear it happens elsewhere too.

  2. Alittlebitoutoffocus

    My Swiss Alpine Club “Our Alpine Flora” book says the Perennial Cornflower (which is one of my favourites btw) is protected in 8 Swiss Cantons, (mainly in the north and north west of Switzerland), so I think the British Columbians and Canadians should be ashamed of themselves. It’s a beautiful plant. I particularly like the geometric shape – with the petals (if that’s what they are called, coming out at right angles. It never ceases to amaze me the different ways plants find to grow. 😊

  3. Toffeeapple

    It is a lovely plant. I used to grow Cornflower and had a wild patch of Greater Knapweed but they have both disappeared. Though another of my favourite blue plants, (the Borage) has re-appeared here; I thought it had gone for good!

  4. Alyson

    A lovely post about a beautiful blue plant – As ever so much of interest here so a joy to read. My mum (who is now in the care home) has always had a favourite summer blouse which is covered in blue cornflowers. I took it in for her recently and am really hoping it doesn’t go astray. So pretty.

    1. Bug Woman

      I empathise re the blouse and the care home – things often go missing, don’t they. The latest loss is my Mum’s address book, which had everyone’s phone numbers in it. Dad is very philosophical, and says that the other folk in the home often take pretty things and he doesn’t mind. I shall be keeping an eye open for it though 🙂

  5. tonytomeo

    One would guess that your weeds, like ours, are from regions of similar climate and terrain. It makes one wonder what mountain plants like about your region.

    1. Bug Woman

      I think mountain plants survive well in urban environments because of things like shallow soil, drought tolerance, exposure – all things that plants in mountain regions would also have to tolerate.

      1. tonytomeo

        It is the opposite of chaparral or desert plants (which are native here) which can not tolerate too much water or root disruption . . . or confinement.

  6. rosni3

    Such an interesting and informative post, as yours always are. Thank you so much for all the work that goes into them. Interesting comments too. How marvellous that your dad can be so philosophical in his take on the kleptomanic tendencies of his fellow-residents. All the same I really hope your mum’s address book turns up.


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