Organic farmers near the Ottawa community of Stittsville say they've had to destroy portions of their crops because the city botched its notification process for spraying herbicides to kill wild parsnip.

Wild parsnip — officially labelled a noxious weed in Ontario last year — has become a concern because the plant's toxic sap can cause skin rashes. The weed also wipes out other species, including flowering plant species that attract bees.

The infestation is growing in Ottawa, and to stop its spread the city has allotted $198,000 in the 2016 budget for mowing and herbicide spraying, up from $100,000 in 2015.

The city sent certified organic farmer Dick Coote of Littledown Farms a notice in the mail saying he could opt out of herbicide spraying along his fields on Mansfield Road. The notice said the city would put up signs in advance in areas it planned to spray to give Coote time to opt out.

But the signs never appeared, he said.

Coote will have to mow down swaths of crops bordering the road for three years because they were exposed to herbicide. (CBC)

'Absolutely no signs went up at all'

"The letter clearly indicated that signs would be put up before any spraying was done. Well, absolutely no signs went up at all. ... [Crews] just suddenly appeared one evening — fairly late, I think it was about eight o'clock in the evening — and sprayed ... and the option for calling in and opting out had been taken away," he said.

Coote said he was forced to mow down some of his organic spelt and hay because of it, and he won't be able to plant or harvest anything on wide strips of land bordering the road for the next three years. Certified organic crops have restrictions on the herbicides and pesticides they can come in contact with in order to maintain their certification.

Bob Whitmore, another certified organic farmer at Whitsend Market Garden, had to do the same with some of his spinach crop. He said the city didn't put up warning signs along his property this year, either.

"As a small businessman I at least expect a bit of predictability when it comes to the rule-making, not having the rules made up on the fly," he said.

Organic farmer Bob Whitmore stands in a section of his property he says he can't plant crops in for three years because the city sprayed wild parsnip herbicide without putting up warning signs. (CBC)

Farmers filing claims against city

Laila Gibbons, Ottawa's manager of parks, buildings and grounds services, says the city decided against putting up signs this year. But she admits they did use the same flyer from last year, which said the city would put up signs in advance.

"No, I don't [find this confusing]," she told CBC News. "I believe it is the landowner's opportunity to call in that number and opt out of the program."

Laila Gibbons, the city's manager of parks, buildings and grounds services, says the city didn't update its flyer to say that signs wouldn't be put up, but that farmers were told to call the city to opt out. (CBC)

"Last year we did it [put up signs] along the roadsides because we did 260 kilometres ... [but we] found that it was a very tedious and very expensive process to do. Because we expanded the program to over 800 kilometres of roadsides this year, it was impractical to do that, and through discussions with the Ministry of Environment and Climate Change, we got the approval to do it through public notifications instead," Gibbons added.

"[The change] may not have been reflected on that flyer itself, but it was done through ... media notifications that did go out, it was on ottawa.ca, it was in community newspapers and a lot of the news channels have picked it up as well. ... Nothing specified no signage, but with the notification process it did specify when [spraying would occur] and that the locations can be found on ottawa.ca."

Coote has now filed a claim against the city. Whitmore says he plans to do the same as soon as he adds up his losses.