Growing bright flowers in shaded areas of the landscape is difficult, as most flowering plants require full sunlight. Tuberous begonia is one of the few flowers that bloom from spring until fall frost that tolerate shade. The tuberous root structure of the begonia is tender, so will not survive winter frost. You can dig it up and store it inside for spring replanting, allowing you to grow the same plants without the need for purchasing new ones. Proper care ensures the tuberous root remains healthy from year to year.
Dig up the begonia tuber once the foliage yellows and dies back, usually after the first fall frost. Dig around the plant until you are beneath the tuberous root, then slide your trowel under the root and lift it from the ground. This prevents the trowel from cutting or damaging the tuber.
Place the tubers in a well-ventilated, warm room to dry for three to five days. Pull off the remaining stems and roots, which should easily detach from the tubers when the tuber is properly dried.
Fill a shallow box with dry peat moss. Bury the tubers in the peat moss and store the boxes in a dry, 55 degree F room until replanting time.
Sprout the tubers in March. Fill a seedling flat with a potting soil then set the tubers in the flat with the indented side facing up. Add additional soil so that the top of the tuber sits ½ inch beneath the soil surface.
Water the soil so it is evenly moist but not soggy. Set in a brightly lit, 65 to 70 degree F room to sprout. Continue to water every three to five days, or as needed to maintain soil moisture.
Transplant the begonia tubers to their own pots or outdoors once they have at least two leaves. Transplant outdoors only if all frost danger has passed. Plant the tubers at the same depth in the bed or pot that they are at in the flat. Space bedding begonia 16 inches apart in all directions.
Fertilize potted tubers once every one to two weeks with a soluble, balanced flowering plant fertilizer, following label application instructions. Fertilize bedding begonias once a month throughout the growing season with a balanced fertilizer, such as 10-10-10 analysis, following label application rates.
Water begonias when the soil surface begins to feel dry. Water potted tubers until the excess moisture begins draining out the bottom of the pot. Water bedding plants until the soil feels moist to a 6 inch depth.