Ken Thompson: how did orange petunias escape from the lab?

If gardeners think about ­genetically modified (GM) garden plants at all, they perhaps consider that it would be nice (although, frankly, also a bit weird) to have a genuinely blue rose, or (weirder still) a red daffodil. The funny thing is, we have already been there, or somewhere very like it, and not recently either.

In a paper in journal Nature in 1987, a team at the Max Planck Institute for Plant Breeding Research in Cologne showed that inserting a maize gene into a petunia enabled it to make the pigment pelargonidin. Pelargonidin, as its name suggests, helps to make pelargoniums (and strawberries and raspberries) red. In a petunia, its effect is a kind of salmon colour. The Dutch firm S&G, now agribusiness giant Syngenta, licensed the technology and by 1995 had developed a vivid orange petunia – a colour that no petunia has ever managed if left to itself.

The new petunia was trialled in Florida but Syngenta never sought market approval; in any case, they couldn’t have been sold in Europe, where there has long been a de facto ban on growing GM plants of any kind. One of many things that we could change after Brexit – if we choose to.

So that was that – or was it? Fast forward to 2015, when Finnish plant biologist Teemu Teeri noticed some orange petunias in a planter outside Helsinki railway station. He took a piece back to the laboratory and eventually confirmed that the petunias had foreign genes matching those described in the 1987 paper. Teemu mentioned his discovery to a former student who now works for the Finnish Board for Gene Technology, and soon the Finnish food safety regulator, Evira, was calling for eight orange petunia varieties to be removed from sale. The EU Commission quickly asked other EU members to follow suit.

How did the orange petunias escape from the lab into the market? No one knows, or at least no one is admitting they know. But it’s not too surprising; companies merge, personnel move on, and before you know it no one knows where seeds came from. In all probability, no one is to blame and it was simply an honest mistake. But it’s clear that, although several varieties have been available for the best part of a decade, there is no authorisation for their sale and suppliers must destroy them. 

Thompson & Morgan has already stated: “We’re not selling any. We’ve withdrawn them from sale.” Orange petunias are not the advance guard of a wave of GM flowers – this looks like a one-off mistake. Nor, given the low probability of gaining approval to sell them, are companies likely to want to invest in the research needed to produce GM garden plants. Getting their fingers burned with orange petunias, albeit unwittingly, won’t encourage them, either.

But as everyone is at pains to point out, orange petunias are about as harmless as it gets; as the Horticultural Trades Association puts it: “Orange-coloured petunias pose no threat to people, animals or the environment.” So what should you do if you have a hanging basket full of petunia ‘African Sunset’? While I’m sure that not immediately incinerating them must be infringing some regulation or other, I think a knock on the door from the horticultural police is extremely unlikely. Just don’t make the mistake of exhibiting them at your local flower show.

And look on the bright side – continuing to grow petunia ‘Orange Punch’ brings with it a frisson of danger that you don’t normally associate with growing petunias.

• Ken Thompson is a plant biologist with a keen interest in the science of gardening. His most recent book is Where Do Camels Belong? The Story and Science of Invasive Species (Profile Books, £8.99). To order, visit books.telegraph.co.uk 

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