The plants were bought at a garden centre four years ago for £2
Police have apologised to an elderly couple after officers raided their home in Bristol believing it to contain a cannabis factory.
Ivor Wiltshire, 77, and wife Margaret, 79, returned from holiday last month to find their front door smashed in.
After finding nothing it later emerged a £2 plant in their garden had been giving off a smell similar to cannabis.
"A couple of pensioners hiding a cannabis factory - you couldn't make it up," said Mr Wiltshire.
An Avon and Somerset police spokesman said: "We can confirm that we executed a warrant as part of our investigations at an address in Coronation Road on 17 October.
"Avon and Somerset Police has received a complaint from Ivor and Margaret Wiltshire and this is being investigated thoroughly.
"Mr and Mrs Wiltshire have received a personal apology from District Commander Andy Francis as well as a financial payment to ensure that they have not suffered any loss as a result of the constabulary's actions."
Mr Wiltshire said when the couple returned to their home in the Kingswood area the police had smashed in the front door and the porch door and left the loft open.
"I can't smell anything and my wife doesn't know what cannabis smells like so we've just gone on what people tell us, she just thought it smelt like flowers.
"If they had only asked me, I would have let them in and showed them the house, the garage and the loft without a problem because I've got nothing to hide."
After police found no evidence of illegal activity in the house detectives discovered plants the couple had bought for £2 at a garden centre were to blame.
The Wiltshires had planted the moss phlox (Phlox subulata) in the front and back of their home four years ago.
And the plants are being blamed for an attack at a neighbour's house in October.
In that incident a knife-wielding gang wearing Halloween masks broke into David Difford's home and demanded that he "give them the weed".
The 54-year-old said he thought he would be stabbed by the gang, who may have been fooled by the smell of the plants around a week before the raid on the Wiltshire's home.
Mr Difford said things have quietened down now the plants have gone.
"The smell from the plants next door has been horrendous - it fooled the police and the druggies into thinking it was the real McCoy," he said.
"I thought it was cannabis myself at first, but now I'm 100% sure it's those plants that have caused all this trouble."