Tuberous Begonias in the Garden

  • Difficulty Rating: Beginner
Tuberous White Begonia potted in Fiskars container

Tuberous begonias are summer garden showstoppers.

They bloom in a rainbow of assorted colors for several months, grow in either upright or hanging forms, and they perform beautifully in the less sunny corners of the garden. Plus, with just a little TLC, they will keep over winter to grow again year after year.

In late winter or early spring, tuberous begonia bulbs begin showing up at the nursery. At this time of year, they are simply lumpy looking bulbs packed into a sawdust-filled box ornamented with photographs of the plant at its peak in summer. Choose firm, not shriveled, bulbs. As well, look for ones with nubby buds rather than any reaching shoots that will easily break. If you miss out on buying them as bulbs, be prepared to pay a bit more for the ones potted, blooming and on sale later in the season. When selecting your bulbs, consider where you plan to plant them. If they will be filling hanging pots, be sure to purchase a variety that will actually hang rather than an upright form, which is more ideal for the mixed border.

 

Red Tuberous Hanging Begonia

 

Getting these bulbs started early will mean a longer season of blooms. If possible, pot up your bulbs according to the directions, in a well-drained planting medium. Water it well, but be sure the soil always remains well drained or your plants may rot. Place your planted container in a warm, protected location to encourage an earlier start to the growing season. A cold frame is ideal. Within a few weeks, you should see sprouts beginning to emerge. Keep your container-grown plants in a protected place until frost and cooler temperatures have passed for the season. Then, move your young plants to your preferred location – somewhere out of direct sunlight that does receive some amount of bright, filtered daylight.

If your goal is to create a border filled with gorgeous begonias, try starting your bulbs in smaller containers earlier in the season following the directions above. Then, carefully transplant young starts into the border after temperatures warm. And, be certain to locate your beautiful begonias in a spot that receives regular water but is never soggy and never in searing sunlight.

 

White Tuberous Begonia Female Flower

 

Begonia flowers – especially the big female ones – are very showy, but they can also be very messy. As they drop, clean them from floor surfaces or you may slip on the slick, decomposing flowers. Or, better yet, be sure to stay on top of deadheading them before the flowers fall. Too, if branches begin breaking under the weight of flowers, carefully stake and brace them. And, keep an eye out for mildew and rot on your plants. This can be a sign of too much soil moisture. If it happens, cut out the rotten portions of the plant, drain any standing water, and hold off on adding more water until the soil begins to dry a bit.

What goes well with begonias? Try pairing them with airy ferns, fragrant heliotrope, taller fuchsia, Mayapples, or a few Hosta for a stunning shady space.

As summer fades toward fall, your begonias will keep right on blooming, but begin to taper off water ahead of freezing temperatures. This will help encourage the plant to enter dormancy. Just ahead of the cold, cut back any lingering foliage and lift the remaining bulb from the dry soil. Store it in a cool, dry location stored in sawdust until you are ready to plant again in the following spring.