I am not a gardener but my wife is. We have a rather intriguing mystery
which I hope you here will find interesting and your interest enlighten
us a bit. Reputably, the best gardeners in the world are from the UK
which is why, although I'm from the southwest USA, I post here.

Last year we had some tomato plants - one in a large pot (roughly 3
gallon size). The potted one was a cherry tomato plant. As the season
went on, all things were normal with these plants.

At the end of season but before the first hard frost, my wife brought
the potted tomato plant into our glassed in but unheated porch. She
figured that it may last long enough to ripen the tomato fruits on it
but as yet still green. They never turned red but also the plant itself
continued to look alive through the winter.

Although the conditions on the porch are less severe than outside,
several times a month for several months the temperatures in that room
fell below 32 f / 0 c.

By spring, the plant still looked reasonably healthy so my wife planted
it in the regular garden along with the other plants. It is growing very
well, and is heavily laden with a new season's worth of fruits. It is
well ahead of other tomato plants started from seeds and transplanted as
seedlings into the garden.

Is this a remarkable thing - a tomato plant lasting more than one year
AND withstanding freezes? Or are we making a celebration over nothing in
particular. BTW, it's fruit now is just reaching ripe - at least a month
ahead of its younger competition.