Will Nonstop Begonias overwinter here in Seattle and do well in subsequent years? Mine are in a north-facing shaded area with good soil drainage.
According to the Sunset Western Garden Book (2007), it is possible but not always easy to overwinter tuberous begonias such as the ‘Nonstop’ series. Most people use pots and bring them into a cool, dry, dark environment (such as a garage) for the winter. Others put tubers in the ground but dig some in fall to overwinter in a cool shoebox full of sand. Sometimes they can survive our Seattle winters in the ground, but that is not a sure thing. For example, neighbors of mine lost their last winter despite a blanket of mulch they hoped would protect them. Freezing weather kills them, and the damp soil doesn’t do them any good either.