He would also donate the produce for unveilings and tangi in the community.
"He would even have people from Brisbane calling months in advance who wanted to purchase some when they came to New Zealand," wife Colleen Mansell said.
He sold the watercress and pūhā at the couple's home in Flaxmere. There was no official business name or website - "everybody just knew they could get their watercress here," Colleen said.
"He was the Flaxmere community watercress picker, everyone knows Tom (Pups) Mansell," Paora Pohatu, a family friend, said.
He was dedicated to providing the watercress to people "far and wide".
"If someone came and bought the watercress in the morning, he would go back out picking to get more for the people in the afternoon," Colleen said.
Tributes posted on Facebook remember Tom and his watercress fondly. Community members refer to him as Pups, papa, uncle or mātua.
"He was papa or Pups to everyone, no one really called him Tom," Colleen said.
Hastings District Councillor in the Flaxmere ward Henare O'Keefe hoped the community man would "rest well".
"The Tom 'Pups' Mansell's of this world provide a bridge of kindness and love, through the simple act of providing watercress.
"People like Tom are what communities are all about, humble never seeking notoriety with a gentle demeanour," O'Keefe said.
While Tom was whānau to much of the Flaxmere community he also had a large family with Colleen.
The couple had three children - Thomas and Della, and Rex, who passed away aged 35. He also had seven grandchildren and three great-grandchildren, many of whom he helped raise.
Tom also involved his mokopuna in the watercress business, often taking them picking with him.
"They were often his helpers, always helping to pick or carry the baskets," Colleen said.
"He taught me how to do everything," said oldest grandchild Sharee Mansell.
Tom and Colleen would have celebrated their 50th wedding anniversary in June this year.
Colleen said with a laugh that he was "a grumpy old bastard" who was an important part of the Flaxmere community and would be dearly missed by all who knew him.