where are you ..

are the plants outside or inside???

is there a chance it could be cold damage.. frost or freeze???

how long have they been potted... any recent transplant??

ken

Madelyn CK, I am not as familiar with the plant as perhaps I should be; but the color of the stalks indicates a disorder. As far down as I could peer, it was all brown; and the discoloration occurs in leaves at that lower level also.

To my mind, it appears to be a systemic disorder - likely terminal.

Mint

Ron, I think that lots of mint have purpley stems.

There have been times when I've wished the mint would get a disease, but even round-up had a hard time killing the stuff. They do like a little shade and damp soil. That's all I know. Pots are hard to control dampness.

Here, it's so hot and dry on this property, they don't venture past their irrigated spots. They won't travel across a desert to find water and shade, so we have them in ground here. I would never have put them in ground again, but they were here when we bought this place. A very nice flavor too. Might be chocolate mint.

Yellowing or browning of a leafs edges may indicate something called leaf scorch, something that happens when a plants leaves loose moisture faster than they can replace it. While that is usually associated with a too dry growing environment it can also occur if the plant is in too wet soil since the roots cannot move moisture that easily in that environment either. Most sources I find refer to this as a problem with trees but
I have seen it in many different plants.

http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/bacterial-leaf-scorch

kimmq is kimmsr