This accident has upset families on the island, who have loved ones buried there.
The council has also been slammed for its lack of compassion in a statement on the matter issued last week.
In the statement, a council spokesman said: “Despite budget cuts, the council works hard to maintain cemeteries and to respect the areas. We have selected to use weedkiller as strimming grass and weeds can damage memorial stones and tributes set out by families for their loved ones.
“While we were carrying out this work in Barone Road Cemetery, Bute, a broken piece of equipment meant that more ground was sprayed than intended.
“We apologise for this but can reassure people that this is temporary as the weedkiller we use is biodegradable which means that it should start to repair in four to six weeks.
“The equipment has been rectified and checks are in place for the future.”
Councillor Jim Findlay was angered by the lack of compassion in the statement.
He said: “My reaction to this incident at the cemetery is disappointment. My further disappointment is with the council press release which offers no apology to the families affected.
“Nobody was looking for an apology for what happened, but an apology for the upset caused. The council apologised for the damage to the grass but not for the distress it caused. The relatives would have been happier with an apology for the distress they suffered as this has caused a lot of anger and distress.
“These things happen. Nobody goes out to do these things knowingly. It’s just a shame how it has been dealt with after the event.”
Argyll and Bute Provost Len Scoullar added: “I have been to see it. It’s a bit of a temporary disaster.
“I have spoken to the people involved in the council and they tell me it was a partly faulty valve on the sprayer leading to a spread much wider than they had thought.
“Apparently it’s non-biological and I was told the affected ground will be capable of replanting in two weeks, and start growing in five weeks.
“I can understand people being upset about it.
“It’s a shame it happened. But I think it was an accident.
“It’s a shame for the people involved who have loved ones buried there. But I have been assured it will be fine in five weeks or so.”