The Argentine ant, Linepithema humile, is a tramp species capable of inflicting severe disturbances on agricultural, urban and natural ecosystems within their introduced range. Abiotic constraints, primarily water and temperature, currently confine the Argentine ant to sub-tropical and Mediterranean climates. Distribution records for Argentine ant in the eastern U.S. north of North Carolina are very rare. Argentine ants persist in North Carolina even though its winters should prove too cold for widespread, year-round survival. We found that Argentine ants survive subfreezing conditions by moving into the soil where temperatures remain above 0°C. Previously, it was demonstrated that Argentine ants ceased foraging when air temperatures were below 5°C, yet, we recorded Argentine ants foraging activity on loblolly pines throughout the winter. The rough bark of these pine trees provides a foraging microclimate up to 20°C warmer than air temperature on sunny winter days. In North Carolina, honeydew-producing hemiptera on pine trees persist throughout winter, thereby providing a winter food source for Argentine ants. Therefore, sub-optimal winter soil temperatures and absence of a winter food provision may preclude Argentine ant spread beyond North Carolina.