A green-thumbed Southampton couple who tried their hand at growing Bermuda sweet potatoes came away with a colossus: at 17.35lbs, it’s the biggest they’ve ever seen.

“I’ve never seen anything like it — when they see it, everybody goes ‘Is that a pumpkin?’” said Sinky Bay resident Wanda (Wendy) Wilson Butterfield, who along with husband Quinton Butterfield dug the giant sweet potato out of the garden this weekend.

The outsize root vegetable came with several weighty runners-up, she added: “I gave one to my mother — she’s 92 years old and she’d never seen anything that big.”

Asked what the secret was, Ms Wilson Butterfield confessed that she had no idea.

Although the family have grown many different vegetables, they are “novices” when it comes to sweet potatoes.

“We used a lot of horse manure as fertiliser; I thought too much,” she said. “That area was a garden 100 years ago and it’s grown a lot of watermelon. I was saying that my father would be proud to see this.”

They still haven’t decided how to cook the giant.

“I love sweet potato and I look for it every year. It’s in itself very good for you, and Bermudians have that taste for their own variety of sweet potato. I just like them plain. You can cook them with codfish and potato or use them in potato salad.”

The plant is a vine, but its underground fruit can be detected after several months by feeling around on the surface.

“We figured six months for sure — then we thought, enough is enough, let’s pull something up,” Ms Wilson Butterfield said. “We got blessed with a big one.”