Mint reverting into parent?

[melop]

Last year I bought some peppermint that I was able to successfully overwinter outside in a pot, but since it's started growing for the new season I've noticed something very strange.
The new growth looks very different from how it used to be.

Before it was more oval with lobed edges, smaller, and didn't have much fuzziness to it. Now the leaves are coming out bigger and more elongated with pointed shape, serrated edges, and noticeable hairs on it. It seems to have lost a lot of that sweet peppermint smell and has almost a more 'bitter' smell. Honestly it reminds me more of regular mint or spearmint.

I guess my question is, could it have "reverted" to expressing the traits of a parent mint? I know peppermints aren't a true variety; they are made by crossing certain kinds of mint. Could the overwintering (US zone 6-ish) have had that effect?
A bit strange perhaps, but I was curious if anyone has seen this before.

[imafan26]

I have grown a few different mints but I have only had the variegated ones revert mainly the pineapple and apple mints. I have not had a peppermint revert to spearmint. But I have had mixed plantings of peppermint and chocolate mint because they look alike and they ended up in the same pot.

[applestar]

I think it's more likely that some other mint -- is it really mint? -- rhizomes were entangled with the peppermint and that one turned out to be winter hardy while the peppermint succumbed to the winter freeze, or else the peppermint is slower to emerge and may show up later.

[ButterflyLady29]

Did you happen to have catnip growing nearby last year? Sounds more like catnip than peppermint.

[melop]

as far as I know it was the only one in the planter. also the old growth turns into the new strange growth, I can even rub the lower leaves to get peppermint fragrance. the top leaves tho are different. it's kind of bizzare chimera action. haha

[KitchenGardener]

For what its worth, this has happened to me on more than one occasion - and in fact, is happening right now! I have even started spearmint from seed, had it live in a pot for a season, and now second season in the pot, I'm watching a portion of what is in the pot morph - more elongated, serrated-looking leaves, slightly darker in color, bristlier stems and generally more aggressive growth habit. Weird!

[imafan26]

If they were grown from seed, they may have crossed. I grow mine from cuttings so they have always come true. I only have problems when I repot more than one at a time because chocoate mint and peppermint look alike.

[applestar]

One other thought -- the leaves change characteristic when they go into flowering phase. Like most herbs, the more desirable leaves come from younger, non-flowering stems.