Not sure of the variety you have there but many mints have tough roots that are able to survive dormant during the dry period. that is what happens here where we have a about the same dry period. Having been plowed repeatedly both the grass and mint probably have that kind of root so the repeated cutting of the roots just propagates it. The permaculture rule is observe what it does and make it a solution rather than a problem. It is noted that the fragrance of its oil is a deterrent to some animals and insects. Note what insects are attracted to its blooms, they are often the predictor insects.
I also have the lemon fragrance type which has week roots but prolific seeds which fit another niche.
Yes, agreed. The 'problem' is the solution and that is why the mint is not being pulled up. Such a delughtful fragrance kucks up when I walk to the compost heap.
I call it a 'weed' because they say weeds speak to you. They tell you a story about your soil (ooops typed soul) but I could not find anything profound about mint on google about the soil quality. As you say probably been inadvertantly propogated in the past.
We must storm this mad man's lab and destroy his villanous bomb! Are you with me tiny ad?