A man who threw a pot plant at his 82-year-old mother and then pawned her belongings while she lay dead on the floor has been jailed for 21 years.

The 59-year-old, suffering from heroin withdrawals, impulsively decided to lift a 15-kilogram pot filled with soil and a partial brick.

She did not know her sister was already dead.

“To my sister, Colleen Wilson … you were taken in an act of greed,” she wrote in a victim impact statement read to the court.

“What happened to you was a selfish and unimaginable way to die.”

A jury found Mapp guilty of Wilson’s murder in October 2024.

His earlier guilty plea to manslaughter was knocked back by prosecutors.

Mapp’s barrister Sarah Talbert previously argued the offence was spontaneous and impulsive, as evident in his choice of weapon.

This incident was the result of long-standing tensions in their relationship rather than an attempt to obtain money for drugs, Talbert explained.

She pointed to previous incidents where her client had been in need of funds and had not assaulted his mother.

Wilson was previously forced to pay $700 to get her TV back after her son pawned it.

But crown prosecutor Carl Young argued Mapp was fuelled by the desire to feed his heroin addiction and intended to kill his mother.

“There were ways to disable his mother that did not include a 15-kilogram pot plant to the head,” Young had told the court.

Justice Harrison jailed Mapp for 21 years, backdating the sentence to the date of his arrest in July 2022.

His non-parole period of 15 years will expire in 2037.

Support is available by calling 1800 RESPECT (1800 737 732), Lifeline 13 11 14, Men’s Referral Service 1300 766 491, or the National Alcohol and Other Drug hotline 1800 250 015.