I am not familiar with gardening in severe climates, but I would suggest, if your weather is already cooling down, that you keep your mint in a pot which can be brought inside when things begin to freeze. Mint is pretty tough, and the mulching idea is a good one - it helps to keep the roots warm - but if you're worried, nurture it until next spring, when the warmer weather will help it overcome any transplant shock.

yeah, I'd grow it indoors then in the spring, gradually acclimate it to the outdoors. I don't know how the Canadian climates work, but you aren't a 9b in the US. how cold does it get there? 10º?

Mints do pretty well inside you may really enjoy it. I have no clue about overwintering as I've never grown things in really cold areas. But for inside, just stick it on your kitchen window or some sunny window, they aren't very demanding, just don't let it dry out completely, they like to be sorta moist. Zone 9b in the us is roughly miami area or deep south texas.

I've grown mint as far north as Minnesota. My mint always came back. However, I think it might be a little late in your season to put anything new in the ground. I too would recommend potting it up and bringing it indoors until your soil warms up in the spring/summer.

Thanks all! i'll go with keeping it inside and, as suggested, in a sunny location with moist soil. Many many thanks for the helpful responses.

If Miami/south Texas are zone 9b, then i am WAY off. Sorry, my fault. During Dec/Jan, our temperatures dip down to -40 C.... average minimum temperature is around -2.1 C, i think. During winter, +10 C is considered an exceptionally warm day for us.

Thank you, again, everyone. Much appreciated.