Patricia Hewitson had been growing petunias in her front garden but in July this year, she noticed an unusual green plant with large leaves taking root between them.
At first the 65-year-old from Exmouth, Devon thought nothing of it but when it grew to 5ft in a matter of weeks and started to smell strangely sweet, she decided to take the matter to the internet and asked her friends to identify it on Facebook.
They couldn't agree what it was and so Patricia sent in a picture to Potting Shed, a gardening programme on her local radio station.
Immediately the experts told her it was the illegal plant - and sent the photo to the police. A mean move?!
Patirica was quoted in The Daily Mail saying: "I don't mind that they told the police. They accepted that I wasn't intentionally cultivating it and said I wouldn't be prosecuted if I destroyed it.
"I did get an email asking if they could come and look in my loft though - but I live in a flat and I haven't got a loft."
It is thought that the cannabis came from a hemp seed that was mixed in with some bird feed Patricia and her husband, John, 70, used.
The police have confirmed that an offence was committed but there were mitigating circumstances and so no charges will be brought.
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