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How to Grow: Tuberous Begonia
Learn how to grow tuberous begonias including information about varieties
Listen to podcast:
Begonia tuberhybrida
Other Name
tuberous rooted begonia
Sun Requirements
part sun, part shade
Bloom Period and Seasonal Color
Summer to fall in a wide range of colors such as red, pink, yellow, orange, white and bi-colors
Mature Height x Spread
8 to 18 inches x 8 to 18 inches
Added Benefits
attracts beneficials, deer resistant
Tuberous begonias are colorful flowers grown from under ground bulbs or tubers that produce beautiful single or double petaled blooms all summer until frost. Until the traditional wax begonias commonly found in garden centers as bedding plants in spring, tuberous begonias have large, showy flowers and put on quite a show. I remember seeing an exhibition of these flowers and they were so perfect it was hard to believe they were real. The plants can be upright or cascading depending on the variety. They are sensitive to wind, rain and adverse weather, but in a protected location, and especially when grown in a container, they’re a striking flower in the garden. Like other begonias, tuberous begonias foliage can have attractive coloring and markings.
Where, When and How to Plant
Tuberous begonias are not hardy in New England, so tubers must be dug and stored in winter or grown as an annual. They can be grown from seed, but it is easier to purchase bulbs or plants in spring from your local garden center. Plant in the garden or a pot after all danger of frost has passed. Tuberous begonias grow best in a partly shaded location protected from the afternoon sun. To get a jumpstart on the season, plant bulbs indoors 8 weeks before your last frost date in containers. Grow in a sunny window and until you can plant them outdoors.
Growing Tips
Tuberous begonias flowers and leaves are sensitive to wind and rain. Plant in a protected area and try not to get the leaves or blooms wet when watering. Many gardeners grow tuberous begonias in hanging baskets under a porch or eave. Fertilize every 3 weeks with an organic plant food and keep well watered. Don’t over water or the stems will rot.
Regional Advice and Care
Keep plants deadheaded to stimulate more blooming. To save the bulbs, in fall before a frost, cut back all the foliage to the soil line, dig the bulbs, let them dry in a warm, airy location for a few weeks and then store in a perforated, plastic bags filled with moistened peat moss in a cool, dark basement. To control powdery mildew disease, clean up diseased foliage, grow in a well-ventilated location and spray an organic fungicide, such as Serenade, to control this disease.
Companion Planting and Design
Tuberous begonias look great planted in small groups or singly in a container. They also look good planted with cascading annuals, such as alyssum and lobelia. In a shade garden, pair them with hostas and bergenia.
Try These
‘Non-Stop’ is a new line of tuberous begonias that is more heat tolerant and doesn’t require dead heading. They come a wide range of colors, such as apricot, red, pink, orange, yellow and white, and have heart-shaped leaves. The ‘Illumination Series’ features cascading double flowers is a variety of colors and bi-colors. The ‘Ornament Series’ features large double flowers, of a variety of colors, on burgundy colored leaves.
Excerpted from my book, New England Getting Started Garden Guide.
Podcast Transcript
This common annual flower is in full bloom now, gracing hanging baskets and containers with its colorful double, sometime fragrant, blooms. It’s origins go back to the Andes Mountains and it was all the rage in the late 1800’s in Europe. But it wasn’t introduced to North America until around World War I when a soldier, Carlton Lowe, saw it growing in Belgium and brought seeds back home to Ohio. What’s the name of this globe trotting flower? It’s the 
tuberous begonia.
Although this flower is stunning when in full bloom, many consider it difficult to grow. There’s nothing worse than seeing a rain stained, wind whipped, powdery mildew ridden tuberous begonia struggling to survive. But, under the right conditions, it’s a show stopper. I once saw a hoop house filled with tuberous begonias at White Flower Farm in Connecticut and it was jaw dropping. Grow these tubers in a bright area with morning sun in containers protected from the wind and rain. If you’ve had trouble with powdery mildew, spray Serenade organic fungicide to prevent this disease. Also, bottom water the plants so the leaves and flowers don’t get stained by water.
The best part of growing tuberous begonias is they can be saved each year. After a light frost, move the plants to a garage or basement and remove the shoots once dry. Take the tubers out of the pot and let them dry for a few days. Store the tubers in dry peat moss in a 40F to 50F degree location. In late winter place the tubers, hollow side up, in a shallow tray filled with light potting soil. Cover them with 1 inch of soil and keep moist. Once they start to sprout, pot them up and let’ em grow.
