Puya Chilensis: Media fooled by “sheep-eating plant”

Puya Chilensis (courtesy strangewonderfulthings.com)
Puya Chilensis (courtesy strangewonderfulthings.com)

Easily the most intriguing thing I read in the last 24 hours was the massive sheep-eating plant about to flower in the UK. Called Puya Chilensis, this plant sounded so much better than a venus flytrap. I needed to know more but now that I do, I’m thinking the BBCHuffington Post and others have likely served up a dud.

The story surfaced on Tuesday when Britain’s Royal Horticultural Society’s media centre put out a gem of a press release. Their South American plant puya chilensis was about to flower for the first time in 15 years. The plant, they said, lived in the wild on the fertiliser provided by dead animals, including sheep, which decomposed trapped in its thick spines.

For the RHA this was a “gruesome secret” where dead animals become the “grizzly (sic) equivalent of a bag of fertiliser”. This is a big claim for a garden in the green heart of Surrey and sheep are big animals to get stuck in bushes. Yet the tale was too enticing to media eager for an off-beat story, and in a great setting. RHS Garden Wisley is so much a flagship of the Royal Horticultural Society it even sounds like one. There, irises and candelabra primulas line the long ponds, roses and salvias sway in the Country Garden, and glorious peonies dazzle and bloom. But does something more sinister live in this part of England’s green and pleasant land?

Puya chilensis is a hardy plant surviving on mostly waterless hills in Chile. It is a terrestrial bromeliad, which means it has one seed-leaf not two and is a cousin of the pineapple. Puya chilensis is common enough in the Mattoral region. However because the Mattoral also contains Chile’s largest cities including Santiago, the constant land-clearing and the plant’s high flammability is making it rare.

What’s also rare, says the RHA, is the striking flowering of puya chilensis. It produces enormous spikes of neon bright, greeny-yellow flowers. The blossoms are gigantic. Individual blooms measure 5cm and they contain enough nectar for a person to drink. Wisley is particularly delighted as it said few UK specimens have flowered, a fact the nursery puts down to difficulties in replicating its natural diet in Chile.

Yet on the Scilly island of Tresco, the Abbey Garden’s puya chilensis has been thriving since 1848 and flowers annually. “Each spring the clumps of puyas send up great spikes of flowers 2-3m high, the flowers clustered at the top,” the garden’s website said. “The actual flowerhead is about 1m long and packed with racemes of chunky flowers, the sterile tips of which stick out, affording a perch for thirsty birds.”  There is no mention of puya’s taste for animals, something you’d think the Tresco gardeners would have noticed in 160 years.

The RHA say puya chilensis uses its razor-sharp hook-like spines to ensnare prey. The animals starve to death and decompose. Finally, after perhaps years, the plant feeds off the fertiliser. Chilean shepherds on the Matorral, they claim, are all too aware of the danger and they usually burn the plant when they see it. Because of the “problematic” food, Wisley feed their puya chilensis with a liquid fertiliser rather than sacrifice a sheep or two.

On the carnivorous plants UK forum, no-one had heard of this strange diet of the bromeliad. “Osmosis” raised the topic on the forum about speculation the plant may derive an advantage from the decaying carcasses of animals it snares in the wild. “I know this is not strictly carnivory,” Osmosis went on, “but with only a slight embellishment it makes a sensational answer to what is the largest carnivorous plant.” Another forum user, “vraev”, made the point carnivory was no longer such a big deal. “It seems almost one plant or another is trying to take advantage of the vast reservoir of animal nutrients,” he/she said.

I’m no botanist but I could find no evidence of carnivorous bromeliads either in scholarly publications or from talking to scientists who work in the field. In fact there is no evidence at all, earlier than the RHA media release of June 18. It is possible this is new science but I’ve not seen any papers. I asked the RHA “if this information has only recently came to light and if so, how?” They have yet to answer my query. The Beeb and Huffpo may have oversold puya chilensis but it doesn’t need to be sheep-eating to be an extraordinary creation of nature.

UPDATE: June 26, 2013. I got this response overnight from Stephanie Shepherd, Senior Press Officer, Art and Gardens:

Thanks for getting in touch. You can find references to the idea that the Puya chilensis derives a benefit from nutrients that leech into the soil from the decomposing carcasses of small animals (particularly farmed sheep) that become caught in its spines in Sharp Gardening by Christopher Holliday and in Maberley’s Plant-book. A Portable Dictionary of Plants, their Classifications, and Uses. 3rd Edition by David J. Mabberley. It has also been referenced by the National Botanic Garden of WalesThe Eden Project and BBC Wildlife Magazine and you can find a piece from Tresco here which references the plant’s reputation for snaring sheep. All of these pre-date the press release announcing the flowering of our Puya chilensis.

As you could probably tell from the tone in which the press release was written, the story was intended as quite a light hearted one and a way of drawing the attention of the wider public to some of the fascinating and peculiar plants that live in our world.

9 thoughts on “Puya Chilensis: Media fooled by “sheep-eating plant”

  1. By watching the size and leaves of Puya chilensis and photos of the colonies, I cannot believe this plant can be so dangerous and has evolved such adaptation to entangle mammals, birds and reptiles, except warding off herbivores. I am glad you share this view.

  2. Please, I’m a chilean biologist and I’ve seen many puyas in my life, I even keep one in my appartment. I’ve never hear something so absurd as the idea that the flowers could trap sheep, it’s ridiculous and probably just a very irresponsible over-statement. That the plant (and probably any plant) can benefits from the nutrients released by decomposing insects and animals leak to the soil is something completly different. Many European media have ecoed this false information, I find it unacceptable that a supposedly serious institution misinforms he public like this.

  3. I wouldn’t be surprised if the publications mentioned in the response letter all fall in a straight line of citation. The Tresco letter is harder to fathom. Have they ever seen sheep caught in these things, or do the farmers simply tell them that they’ve seen that? Sounds like something a farmer might make up to justify destroying the his ancestral homeland.

  4. I’m an ecologist, and I do reserach on Puya plants in the Andes. I have only recently discovered the media fuss about this plant. Even though several years have passed since the original story, I though I would try to clarify since the story pops up near the top if you search for Puya chilensis.

    Happily, Puya plants do not trap sheep in their thorny rosettes. Although I have fallen into Puya plants by mistake several times–an occupational hazard–I have always got out again, though sometimes it can be a painful experience. I’m not woolly, but I can’t see how that would make things so much worse.

    The origin of the idea was a very brief hypothesis, suggested by a couple of ornithologists in the Canadian Journal of Botany in 1980, that Puya raimondii captured birds in its rosette. This plant is very large with rosettes up to 5 m across, and they had noticed remains of dead birds amongst the leaves of a small number of plants. It was an interesting suggestion, but it did not stand up to scrutiny and it faded away (or I thought it had). Given that it is the main perching and nesting plant in its treeless landscape it is probable that birds die of natural causes and fall into the rosette from time to time. Gardeners will be familiar with finding corpses under trees from time to time. Healthy birds are constantly moving in and out of the rosettes without any difficulty. The original article briefly mentioned sheep as an even bigger potential victim. Although an occasional unlucky sheep could stumble and fall into a rosette from above on a steep, rocky slope, this is nowhere near common enough to represent an evolutionary strategy on the part of the plant. Bear in mind also that sheep were introduced by European settlers only relatively recently.

    Why am I bothering to write all this? One might call the original press release light-hearted, and the idea of a sheep-eating plant is a fairly transparent (and successful) attempt to call attention to the press release. As we can see in the reply from the originators of the press release, people naturally assume that a story which is repeated several times is true, without bothering to check the real facts. In this case, it is worse still because the original hypothesis has now been changed for another smaller Puya species.

    Several Puya plants are vulnerable to extinction, especially Puya raimondii. It would be a pity if a story like this contributed to the plant’s extinction by encouraging local people to destroy it for fear of losing livestock. This story of a sheep-eating plant was taken up by the media around the world and makes the story seem true to people who accept this kind of thing without stopping for a moment to think. Top marks to

    It is irresponsible, as an earlier Chilean biologist wrote. People who have the job of promoting stories in the media have an ethical responsibility not to do harm if their story takes off, especially if work for an organisation like the Royal Horticultural Society. I’m disappointed.

    So, for those of you who liked the idea of a sheep-eating plant, I’m sorry it’s just not true. But they are still fascinating and beautiful plants. Enjoy them for what they really are.

  5. This plant was discussed on Canadian radio today because our Royal Botanical Gardens in Burlington Ontario has one in bloom right now. The fellow interviewed also took a lighthearted view of the sheep eating thing, but seemed to have his facts right. I looked up the plant on the internet, and was happy to find this post.

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