Tuberous begonia is such a delight in the garden that many home gardeners want to have many more of them. Why go to the expense of buying new plants when it's easy enough to propagate them?
According to the American Begonia Society, tuberous begonias can be started from seed, stem cuttings, leaf cuttings or from tuber sections. Just follow these steps to propagate tuberous begonia by using the tuber method.
Step 1: Wait Until Foliage Dies
Tuberous begonia plants all go dormant in the fall. When all the leaves have fallen off, dig up the tubers. They will need to be stored for the winter.
Step 2: Rinse Off Tubers
Some begonia aficionados say you should rinse off the tubers and allow them to dry a few days. This probably can’t hurt and will certainly clean off the tuber to allow maximum viewing for the next step.
Step 3: Division
When the tubers are dry, snap them off into divisions. Again, some begonia experts say to snap away the old growth. Small tubers have 2 or 3 stems, while larger ones have 3 to 6 stems. The American Begonia Society’s Brad Thompson says that tubers can be sectioned “like potatoes with at least one eye per section.” This eye may also be referred to as a bud.
Remove one main tuber. Some species form clusters of tubers which can be separated and planted individually.
Step 4: Dust With Fungicide
Use a fungicide to prevent rot and allow the wounded tuber sections to heal a few days.
Step 5: Store Over Winter
Place tubers in a jar or sealed container and keep in a cool, dark place. Temperatures should hover between 40 and 50 degrees F.
Step 6: Place In Sand
In the spring, set the tubers to be propagated 1/2-inch deep in sand in a 3-inch growing pot or container. Bottom heat on the growing container will encourage more rapid growth. Water just enough to keep the container from going completely dry.
Step 7: Pinch Off First Buds
To promote more healthy plants, pinch off the first buds to appear. New growth will then become more profuse, allowing the newly-propagated tuberous begonia to be transplanted at the appropriate time into a larger pot or directly into the outdoor garden.
Propagating tuberous begonia using the tuber method is only one way of adding to the begonia collection. Also try propagation using stem cuttings, leaf cuttings or by starting begonias from seed. Any of these propagation methods—or all of them—can result in spectacular begonias in the home garden.