In the last two weeks, we’ve looked at this year’s National Garden Bureau bulb of the year (allium) and perennial of the year (delphinium). The next plant in this year’s lineup is the annual of the year -- begonia.
With over 1,700 species, the begonia family is the fifth most diverse class of plants. Begonias are often found wild from South and Central America to India. It is impossible to know exactly where they originated, but stories of plants matching their description date back to 14th century China.
Begonias officially got their name in 1690 when a French botanist, Charles Plumier, named them after a fellow French botanist, Michel Bégon.
Of the 1,700 species of Begonia, only a few are commonly used as houseplants or in landscapes. Here are the major classes that you will find available from garden retailers:
* Begonia semperflorens-cultorum, or “wax begonias,“ are the most common. Plants are small mounds (8-12 inches) with rounded leaves and blooms. Flowers range from white to scarlet red. Wax begonias are annuals in Nebraska and are widely used as summer bedding plants.
* Begonia tuberosa, or tuberous begonias, typically have large flowers in a broad color range. Flowers can be huge and double. Since the plants are monoecious, there are always both single (male) and double (female) flowers on the same plant. The leaves are usually asymmetrical, hairy or fuzzy and have a serrated edge.
Tuberous begonias are used outdoors for color in summer containers, hanging baskets or ground bed plantings. They can also be grown indoors as houseplants but require an annual resting period in winter. At the end of summer, stop watering and allow plants to go dormant. Lift the tubers from the soil and trim off any remaining growing shoots. Store the tubers in dry peat moss in a cool, dry place until February. Then they can be repotted and encouraged to begin growth for another year.
* Begonia boliviensis, or Bolivian begonia, is more heat tolerant than other begonia types. The plant branches cascade down in hanging baskets or window boxes. The leaves are similar in shape to tuberous begonias but are narrower and smooth. The flower has long, strap-like petals forming a soft trumpet. "Bonfire" is a popular cultivar, covered with fiery, scarlet-orange flowers and is easy to grow. They even have good heat and drought tolerance, which is unusual in this genus. Bolivian begonias are technically also tuberous plants, and will require a winter rest period before growing another season.
* Begonia hiemalis, also called Elatior or Rieger begonia, typically have small to medium double flowers in a wide range of colors. These are often sold around the holidays and grown in Nebraska primarily as houseplants.
* Begonia rex, or Rex begonias, are also usually grown as houseplants in Nebraska for their beautiful leaves, which are quite hairy or fuzzy and usually covered with multicolored, intricate swirled designs. The Jurassic Rex begonia series is eye-catching with large leaves and bold color patterns. However, find a good location with protection from the wind and Rex begonias can also be used outdoors in summer containers. Be sure to provide them with plenty of water.
* Another large group is the rhizomatous begonias, which actually encompass several begonia species. These plants grow from thick, fleshy stems and have large, colorful leaves. In fact rhizomatous begonias are often grown more for their attractive leaves, rather then for their flowers. The leaves can be round or heavily lobed like a grape leaf. Some have small white flowers in the spring, and a few varieties bloom all summer. In Nebraska, these begonias are usually grown as houseplants.
One of the most common rhizomatous begonias, begonia masoniana, is also called Iron Cross begonia, and has bold color patterns on leaves that are textured with puckers and appear coarse.