The apparent robbery attempt happened Tuesday morning in an east-side neighbourhood.
Police say the victim was in serious condition when he was taken to hospital.
His wife, who was outside with him at the time, was not hurt.
Eighteen-year-old David Kendall Williams, and a 17-year-old male are each charged with robbery, aggravated assault, two counts of possession of stolen property under $5,000, theft under $5,000, break and enter to commit theft, and possession of a weapon dangerous to the public.
Williams is also charged with assaulting a peace officer.
Police Insp. Joel Whittaker says it's alarming that two people who were gardening and minding their business were attacked by strangers in their own yard.
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