I have a small mint plant that a friend grew from a cutting and gave me. He had it in a tiny pot, so I transferred it to another pot in pretty short order, and it's certainly been growing. I have not yet used any sort of fertilizer on it. Recently, I've noticed some of the stems are purple, and those purple stems have dead leaves. Here's a picture:

enter image description here

One possible cause that I'm aware of is that it's gotten too much water. I generally keep it out on a window sill, but it's been raining a lot the past few days. Would it be better to keep it inside until the weather clears up (or at least until the soil dries out a bit)?

But more to the point, should I actually be worried about this at all, or is this considered normal behavior for mint?

  • 1
    I've looked at the image you provided - the leaves seem somewhat small for regular mint, and I'm wondering whether its actually Pennyroyal, which is in the mint family and has a strong minty smell. But Pennyroyal is considered a medicinal herb rather than a culinary one - does the parent plant this cutting was taken from have larger leaves?
    – Bamboo
    Commented Apr 13, 2016 at 11:54
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    Purple is completely normal for mature stems. Also, mint is very a tough plant.
    – alexw
    Commented Apr 13, 2016 at 18:42
  • It's the size of the leaves that make me think its Pennyroyal, that's why I'm asking, although Pennyroyal does have reddish stems, sometimes green. If its pennyroyal, you wouldn't want to be making mint sauce with it...
    – Bamboo
    Commented Apr 13, 2016 at 18:47
  • That's in interesting observation - it never actually crossed my mind that it might not be mint. I'll get a picture of the parent plant on Sunday. I've been making mojitos with this. Assuming it's Pennyroyal, is that a bad thing?
    – Fibericon
    Commented Apr 14, 2016 at 3:40

1 Answer 1


Looks pretty healthy to me. A lot of plants in the mint family get purple stems as they mature.

It's not unusual to have a mix of dying, seeding, and new growth intermingled in common mint. Even when the whole of the plant seems to have died back, you can still have new runners appear from underground later.

Common mint thrives along riverbanks or under dripping taps, so it's pretty hard to waterlog, it's more in danger of death from drying out if it's too long between water or burning in the hot afternoon sun, especially if it's kept in a pot.

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