So glad you asked! In mild winter areas where there is plenty of frost and light snow but the ground does not freeze past a few inches down, dahlias can be overwintered without digging them out of the ground. Simply cut the stalks back to ground level at the beginning of October or when you see the foliage turning yellow. Then cover the ground with a tarp or waterproof table cloth to keep out the rain. You can add a mulch of wood chips or branches on top of the covering to hide it. In May take away the covering, bait for slugs and your dahlias will return. No tarp? You can also use a layer of sword fern fronds or even a pile of maple leaves to repel the water. Keeping the soil dry in the winter preserves the dahlia tubers. Keep growing, Marianne Binetti