Our annual wild flower patch, including Corncockle (left and centre: pinky-purple flowers)
Corncockle, Agrostemma githago, is one of my favourite wild flowers. We grow it in the garden, in our annual wild flower patch and at the allotment. It’s also suitable for growing in a pot with other cornfield annuals.
Corncockle is a hardy annual in the Carnation family, the Caryophyllaceae, whose members include carnations and pinks (Dianthus), campions, catchflies (Lychnis) and Chickweeds (Stellaria). It has an upright growth habit with long, narrow and softly hairy leaves and single pinky-purple flowers from June until August. These are followed by a seed capsule full of heavy, black seeds. These are very easy to collect in late summer, to sow elsewhere, or you can leave them to fall. They tend to stay around the site of the original plant, meaning you can have a patch of Corncockle in the same place year after year. You can simply let seed drop onto the soil, or give it a bit more care, as described in this article: “Grow Corncockle From Seed” Ideally, sow the seed in spring.
Corncockle flower
Corncockle was once common in wheat fields and is thought to have been introduced into Britain from Southern Europe along with crops, in the Iron Age. It is one of a number of plants introduced long ago, known as archaeophytes. (If you want to read more, I recommend “Alien Plants” by Stace and Crawley, 2015, one of the New Naturalist series. A complete list of British archeophytes is in Appendix 2.) Corncockle occurs as a weed in the United States but in the British Isles it is extinct as an agricultural weed, where it has been reintroduced in wild flower seed mixtures.
You can buy Corncockle seeds on their own from Emorsgate Seeds and they are often available in annual wild flower mixes, such as the free packets of seeds supplied by Kew Gardens’ Grow Wild project for several years. We planted this seed mix in Wensum View Park in Norwich a couple of years ago, where it made a very pretty display.
Corncockle seeds and leaves are poisonous but as writer John Robertson puts it: “It is only poisonous if you eat it and there’s absolutely nothing about the corncockle that’s going to encourage you to eat it.”
Corncockle contain a variety of compounds, including the saponins githagin and agrostemmic acid. However, these compounds are poorly absorbed by the body and most will pass through the gut without causing harm. The leaves can be cooked and eaten, according to the Plants For A Future website – thorough cooking, with a change of cooking water, is thought to remove most of the saponins. However, I haven’t tried eating Corncockle leaves and the Plants For A Future website describes them as “a famine food – used when all else fails“. The plant has several medicinal uses and is a diuretic, expectorant and vermifuge.
Until modern methods of farming and food preparation were developed, Corncockle seeds were difficult to separate from harvested grains and would have been eaten accidentally as a food contaminant. York Archaeological Trust has published a fascinating article about Corncockle, entitled ‘The COCKLE of Rebellion, Insolence, Sedition…’ – The Corncockle, by Allan Hall. This mentions that Corncockle seeds were found in excavations in York and in a late 13th / early 14th century cesspit in Chester, having passed through the human gut. The article records that Gerarde, the 17th Century herbalist, wrote “‘what hurt it (cockle) doth among come, the spoyle unto bread, as well as in colour, taste, and wholesomeness… is better knowne than desired’. The quote is also used in “The Running Hare: The Secret Life of Farmland“, by John Lewis-Stempel (Doubleday 2016). There is at least one known case of someone dying from eating bread contaminated with large quantities of Corncockle seed. However, mild poisoning was more likely, where symptoms included “nausea, belching, headache, dyspepsia, and unpleasant taste in the mouth, a tickle in the throat, hoarseness and coughing, with increased mucous secretion. Stronger doses led to dizziness, restlessness, delirium and eventually convulsions and injury to the circulatory system“.
Chickens can be affected if they eat Corncockle seed: they can “present a generally listless and unkempt appearance with rough feathering and diarrhea”, according to the United States Food & Drug Administration. The Illinois Noxious / Invasive Species factsheet states that “The green parts of corn cockle contain so little poison that animals can browse them freely without showing any ill effects. But the seeds are so poisonous that any animal may die from eating ¼ to 1 pound ground cockle seed per 100 pounds of body weight.”
Corncockle seed and its potential use as a poison features in “The Accusers” by Lindsey Davis, which I have just finished reading. It is one of twenty very entertaining books featuring Marcus Didius Falco, a laid-back Roman informer, set between 69 and 77AD.
Kew Gardens’ Grow Wild project is a “the UK’s biggest-ever wild flower campaign, bringing people together to transform local spaces with native, pollinator-friendly wild flowers and plants“. Communities are encouraged to grow our native wild flowers and, by doing so, provide homes and sustenance for insects such as solitary bees.
During 2014 the BBC’s “Countryfile” programme helped to publicise the excellent work being done by the Grow Wild project but The Telegraph, rather than give its blessing to this attempt to make our landscape more beautiful and diverse, decided to use corncockle (figuratively) as a club to hit the BBC: “Project promoted by BBC spreads poisonous wild flowers across Britain“. The Express did nothing to soothe nerves, with “Look but don’t touch! Pretty flower so poisonous that it could KILL returns to the UK” when the plant was found growing in the Sunderland area. “Residents are urged that if they do see the corncockle, they should not disturb it in any way“. In Wootton Bassett, Corncockle plants were fenced off and the flowers were cut to stop the plants from seeding.
If I believed what I read in certain newspapers, I would probably be wearing a biohazard suit by now. Fortunately Patrick Barkham, writing in The Guardian, gave a much more balanced view, as did John Robertson on his The Poison Garden website.
I encourage you to grow this lovely plant and to beware of dubious news stories. The Finnish website NatureGate has some lovely photos of Corncockle, which amply demonstrate why you should grow what is sometimes called the “crown of the field“.
