Seemingly infinite variety characterizes the genus Begonia. Plants can be long-stemmed or low-growing, have fuzzy or shiny leaves, and produce large flowers or ones so insignificant as to be almost invisible. Probably the most prized though not the most widely grown are tuberous begonias, whose name belies their fulsome displays of mid- to late-summer bloom. The flowers often resemble roses or carnations, and they rarely disappoint growers.
“In my garden I always have begonias,” says Steven Frowine, respected consultant to the horticulture industry. “But I have to be selective in what I grow for my own pleasure. They come in strong primary colors and great pastels, and they bloom constantly, from summer until frost. I don’t know of anything else with the same combination of flower size and shape that blooms in the shade.”
Over the years, breeders have developed strains of tuberous begonias (B. tuberhybrida) that feature ruffled double flowers and “rose form” blooms, and some types have flowers that look like carnations or double camellias. Colors range from white through yellow, orange, apricot, pink, and red. Some have bicolor petals, such as white with a pink edge or yellow with a red edge. Begonias with petals that are edged in lighter or darker colors are called picotee.
What to Look for When You Buy
Buy dormant tubers in winter, either by mail from a specialty nursery or from a nursery or garden center. Another possibility is to buy blooming plants in summer. (By the way, tuber size does not predict plant or flower size.)
Most gardeners buy dormant tubers, which are easier to grow than seed and less expensive than blooming plants. Tubers are also usually easier to find than blooming plants. Although it’s possible to find tubers in nurseries in regions where they grow successfully, the best selection is from specialty dealers. Most of their plants have been grown from seed strains carefully bred for high-quality flowers.
Certain dealers also sell named varieties grown from stem cuttings, such as ‘Avalanche’, ‘Bonfire’ and ‘Falstaff’. These are considerably more expensive (ranging from $8 to as much as $75 each) because the supply is limited and cutting-grown tubers take longer to reach an appropriate size for sale.
Blackmore & Langdon, England’s foremost begonia dealer, is perhaps the world’s best-known grower of cutting-grown tubers. In this country, these tubers are available from White Flower Farm. And last year the well-known Antonelli Brothers Begonia Gardens in Santa Cruz, California, began selling its own collection of cutting-grown tubers.
Many gardeners shy away from tuberous begonias because of their reputation for being difficult to grow. They really aren’t. Although travelers discovered the ancestors of these beauties in the Andes Mountains in the mid-nineteenth century, more than half of the United States has microclimates or growing conditions that can sustain tuberous begonias.