A 40-year-old man from Greater Manchester has been jailed for nearly four years after cutting another man's ear in half during an attack.
Anthony Ruchat was arrested in January
Gardener Phil Scanlon needed surgery after Anthony Ruchat, who was described as a "bully and a thug", attacked him with a foot-long bowie knife.
Ruchat, of Sunningdale Drive in Irlam, thought Mr Scanlon had offended his father Manchester Crown Court heard.
He was found guilty of assault after a trial last month.
Ruchat was sentenced to serve three years and 343 days in prison
Trafford council worker Mr Scanlon, 43, had been cutting the grass on Hallcroft in Partington when Ruchat's father came out of his home and asked the gardener not to cut the grass near his wall.
A police spokesman said the attack on Phil Scanlon was unprovoked
Mr Scanlon agreed, the court was told.
Later, Mr Scanlon was packing equipment away with his colleagues when a car driven by Ruchat pulled up nearby.
Ruchat got out of the car and approached Mr Scanlon, saying: "Who's been going off to my Dad?"
Ruchat then pulled a 12in (30cm) knife from his jacket and slashed at Mr Scanlon's face, slicing his ear in half and leaving a large gash in his left cheek before driving off.
Mr Scanlon was taken to Trafford General Hospital for emergency surgery.
Ruchat went on the run and was arrested in January this year.
Det Con John Graham-Cumming said the "viciousness" of the attack was shocking and was completely unprovoked.
"Not only had Phil done nothing to aggravate Anthony Ruchat, but he had actually agreed to his father's ridiculous demands not to cut the grass by his wall.
"He was just trying to do his job.
"Ruchat is a bully and a thug, and he has permanently scarred Phil.
"I hope that today's result will bring him some sense of relief and he can put this awful incident behind him," he added.