As the days shorten and the angle of the sun changes, I, your mint plant, begin to sense the profound shift in the seasons. The diminishing light is my primary cue. My growth, once vigorous and rampant, starts to slow. The cooler air temperatures that follow signal that it is time to conserve my energy. You might notice my leaves becoming smaller and my stems becoming a bit woodier; this is not a sign of sickness, but rather a natural hardening-off process. I am preparing my tissues to withstand the coming cold, reducing the amount of succulent growth that would be easily killed by frost.
When the first frost kisses my leaves, it is a definitive end to the growing season above the soil. The water within my leaf cells freezes, causing the cell walls to rupture. This is why you will see my top growth turn black and wilt. Do not be alarmed; this is a expected part of my cycle. My focus now turns entirely to my hidden, most vital part: my root system and the runners (stolons) beneath the soil's surface. These underground stores are packed with the energy I've spent all summer producing, and they are my ticket to surviving the winter and re-emerging in spring.
Beneath the soil, my world changes too, but more slowly. The earth acts as an insulating blanket, protecting my roots and nodes from the extreme temperature fluctuations above. My entire survival hinges on the soil not freezing solid for prolonged periods, which would damage my root tissues. If a deep freeze is coming, a thick layer of mulch is the greatest gift you can give me. A generous 4-6 inch blanket of straw, shredded leaves, or pine boughs placed over my resting place after the ground has chilled (but before a hard freeze) mimics the natural leaf litter of a forest floor. It regulates the soil temperature, prevents damaging freeze-thaw cycles, and holds in precious moisture.
Perhaps a greater danger to me than the cold itself is wet, waterlogged soil combined with freezing temperatures. While I enjoy consistent moisture during the growing season, sitting in frozen, soggy soil during my dormancy can cause my roots to rot and decay. Excellent drainage is paramount. If I am planted in a container, I am exceptionally vulnerable. Pots offer little insulation, and my roots can freeze solid. For potted mint, you must move me to a sheltered location like an unheated garage, shed, or against a sheltered side of the house. Water me very sparingly throughout winter, just enough to ensure my roots do not desiccate completely, as I am still alive, merely sleeping.
My reawakening is a slow and gradual process guided by the warming soil. As the sun gains strength and the ground temperature steadily rises, the energy stored in my roots will trigger new growth. You can gently remove the winter mulch once the danger of a hard frost has passed to allow the sun to warm the soil. Soon, you will see tiny, bright green shoots emerge from the nodes on my runners, and the cycle will begin anew. Your care in protecting my foundational parts during the cold ensures I can burst forth with vigor once again.
