Is it possible to leave Tuberous-rooted Begonias in the ground over Winter?
Would they flower again as well in subsequent years?
I have always lifted them, once the flowers have finished and the leaves are starting to drop off, dried them and kept them for future years, restarting them off again in Spring.
But I am thinking of having a huge display of these Begonias as “bedding plants” next year, and it will be too much work (and I have not enough storage-space) for me to lift them and dry them all out. What will happen if I leave them in the ground?
Would they just rot away?
Most tuberous begonias would probably not survive this, because the ground would get too cold during the winter. One variety that your plan may work for is Begonia grandis evansiana, known as the hardy tuberous begonia, especially if it is provided with mulch for some protection from cold.