plant of the month
Begonia x hiemalis
(syns.: Begonia x elatior,
Begonia Elatior Hybrids)
Begonia x tuberhybrida
(syn.: Begonia Tuberhybrida Group)
B. x hiemalis:
B. x tuberhybrida:
Hybrid tuberous Begonia,
Note: Wax Begonias (B. semperflorens) are not mentioned in this article because they are available primarily as bedding plants rather than potted houseplants.
Winter-flowering, or Rieger, Begonias (B. x hiemalis/elatior) produce either single-flowered or double-flowered blooms that have rounded petal edges, grow up to 2 inches in diameter and occur in loose clusters at stem ends. Compact varieties reach 6 to 8 inches in height although other types can grow to 12 to 18 inches. Leaf forms are generally rounded, sometimes with scalloped edges, but they also can be ivylike or pointed.
Tuberous Begonias (B. x tuberhybrida) are the large-flowered types, with blooms up to 4 inches in diameter. The blooms are usually borne either in clusters of three, with one male and two female flowers, or in pairs. Male blooms are larger than female blooms and can be singles, semidoubles or doubles while the female blooms are usually single flowered. The blooms, some varieties of which are fragrant and can resemble either small Camellias or roses, are composed of many overlapping petals, often with frilled or ruffled edges. Compact varieties usually reach about 12 inches in height while others can grow to 24 inches. Also, there are pendulous, or cascading, types (B. x tuberhybrida pendula), which are good for hanging baskets. Leaves vary in shape from elongated hearts to pointed ivylike forms.
Characteristics common to all Begonias are fleshy stems and lopsided leaves, with one half larger than the other.
Flowering Begonias are available in red, pink, rose, orange, salmon, yellow, white and bicolors.
Depending on environment and care, winter-flowering (Rieger) Begonias generally last four to six weeks although some new varieties last longer. To prolong flowering time, gently pinch off individual blooms as they fade. This fibrous-rooted species is bred for a single season and can be challenging to regrow (although it can be done), so many people discard them after flowering. Tuberous Begonias typically last two to four weeks, sometimes longer, and are easier to regrow.
Both types of potted flowering Begonias should be available throughout the year. While all growers may not produce these plants year-round, varying production schedules among growers should make them available continuously.
in-store and consumer care
Indoors, flowering Begonias require moderate to bright light but away from direct sunlight; east-facing windows provide ideal exposure. During winter months, they require increased light, so placement near south- or west-facing windows is beneficial.
Begonias prefer moderately moist—but not soggy—soil from spring through fall (drier in winter). They are easily damaged by overwatering, yet they also are adversely affected if their soil becomes too dry. A general rule of thumb is to allow the top inch of soil to become nearly dry between waterings. Water with soft, room-temperature water.
Average room temperatures—65 F to 75 F—are ideal. These plants are easily damaged if exposed to temperatures lower than 55 F.
Begonias require humid environments. Place pots on pebble trays, place a humidifier in the room or frequently mist the air around the plants (never spray the plants directly).
These plants are sensitive to ethylene gas, so make sure your purchases are treated with an antiethylene agent at the grower or during shipping, keep them away from fruit and other produce, and take precautions to reduce levels of ethylene in your facilities.
During flowering and growth periods, feed Begonias every two weeks with a liquid, high-phosphorous plant food diluted to half strength.
Begonias require a light, well-draining potting medium, preferably containing Sphagnum peat moss and/or perlite. African violet potting mix works well for these plants.
Carefully remove blooms as they fade.
Winter-flowering (Rieger) Begonias like to be slightly rootbound and generally need no repotting; they tend to become dormant or die after flowering. Tuberous Begonias may be repotted after flowering, if rootbound, but avoid replanting them into large pots because this can lead to overwatering and, therefore, root rot.
Begonias often react badly to changes in their environment, so instruct customers to provide optimum conditions and care when they first get them home. Some Begonia authorities suggest enclosing plants in a loose plastic bag for a few days to protect them from drafts and dryness and to help them adjust to their new environment.
LEAVES TURN YELLOW OR BROWN AND FALL OFF
Overwatering or underwatering, not enough light and/or too high temperatures.
BROWN TIPS / EDGES ON LEAVES
PALE, ROTTING LEAVES
FLOWER BUDS DROP
Low humidity or underwatering.
Mealybugs, red spider mites, thrips, aphids and root nematodes. Remove mealybugs with a cotton swab dipped in isopropyl alcohol, repeating every five days until the problem is controlled. Treat for mites, thrips and aphids with a nonoil-based insecticide. Removal of affected leaves and stems might be required, or in severe cases, the plant might have to be discarded.
Powdery mildew (white powdery spots) and Botrytis (gray, moldy blotches), both fungal diseases, can occur with overly damp conditions, low light, low temperatures and poor air circulation. Remove infected parts, treat with a systemic fungicide, and improve care and environmental conditions.
To view 51 additional varieties of Begonias, please download the PDF.
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WHAT’S IN A NAME The genus Begonia is named for Michel Bégon (1638-1710), a French naval officer; botanist; and governor of Santo Domingo, in the Dominican Republic, which was then a French colony.
The specific epithet (species name) “hiemalis” is a derivative of the Latin word hiems, meaning of winter. “Tuberhybrida” refers to tuberous-rooted hybrids.
RIEGER OR REIGER There is much discussion about which is the correct spelling. We find more evidence in favor of Rieger, because the hiemalis/elatior hybrids were developed by Otto Rieger, a German plant breeder (although there are those who insist Otto’s surname was spelled Reiger!).
FAMILY MATTERS The huge Begonia genus, with more than 1,000 species, is the lone member of the Begoniaceae family.
HOME SWEET HOME Begonias are native to the moist tropical and subtropical regions in both hemispheres and of all continents except Australia. They are most diverse in South America.
Some information provided by:
Botanica, by R.G. Turner Jr. and Ernie Wasson
Chain of Life Network®, www.chainoflifenetwork.org
Complete Houseplant Survival Manual, The,
by Barbara Pleasant
Dictionary of Plant Names, by Allen J. Coombes
Houseplant Encyclopedia, The,
by Ingrid Jantra and Ursula Krüger
New House Plant Expert, The, by Dr. D.G. Hessayon
New Pronouncing Dictionary of Plant Names,
by Florists’ Review
SAF Flower & Plant Care,
by Terril A. Nell, Ph.D. and Michael S. Reid, Ph.D.
Stearn’s Dictionary of Plant Names for Gardener,
by William T. Stern