Begonias are found wild in South and Central America and many are native to India and other tropical countries. Begonias are grouped into seven classifications: Cane-stemmed - frost tender, grown mainly for their pretty, heart-shaped leaves; Rex-cultorum - grown for their decorative foliage. Needs a 70- to 75-degree temperature; Rhizomatous - grown for their attractive leaves and/or blossoms. Needs around a 66-degree temp. and water from below; Semperflorens - grown for their clusters of rounded flowers. Plant when danger from frost has passed; Shrub-like - grown for their leaves and habit of growth. Needs humidity and bright light in the winter to intensify leaf color; Tuberous - grown for exhibition, as pot plants, or for summer flower beds. The tuberous Begonias have large underground tubers and flowers in almost every shade. Some flowers have frilled petals, some are crested. They can be about 15 inches in height with large, glossy leaves. They will die in the fall but will send up new shoots in the spring. Some Tuberous Begonias are nice to plant in hanging baskets because they grow long, thin shoots and produce clusters of flowers; Winter-flowering - have bronze-green leaves and tons of flowers during the winter. One Begonia from each group will be described below; others will be mentioned in the varieties section.
Cane-stemmed - B. 'Orpha C. Fox' is an erect-growing plant, which has evergreen, oval leaves, growing up to 6 inches long. They are gray-green, splotched with silver and maroon beneath. Its single, rose-pink flowers grow up to 1½ inches across and are produced in little bunches, in the summer mainly.
Rex-cultorum - B. 'Merry Christmas' grows erect, from 10 to 12 inches high, and produces beautiful heart-shaped leaves, 6 to 8 inches long. They are bright red, edged in emerald green with a reddish-pink center. The single flowers grow ½-inch across and are pale rose-pink. They are produced sparsely from fall to early winter. This plant is mainly grown for its gorgeous leaves.
Rhizomatous - The Iron Cross Begonia, (Begonia masoniana) has evergreen, warty, oval-/heart-shaped leaves, which grow up to 8 inches long. They are dark green with red hairs and are marked by bands of dark brown with a central mark that is cross-shaped.
Semperflorens - These bushy, compact plants are commonly called "Wax Begonias" because their evergreen leaves are round, fleshy and waxy in appearance. They produce single flowers throughout the year, but in profusion during the summer. They grow up to an inch across and may be pink, white, red, or crimson.
Shrub-like - B. serratipetala is a very attractive, trailing plant, which grows up to 18 inches high and wide. Its 3-inch long leaves are oval and deeply toothed with wavy edges. They are dark green with elevated, dark pink spots.
Tuberous - B. 'Can-Can' is a variety with upright growth. It is a very beautiful plant grown for its gorgeous flowers. They are double, up to 7 inches across and produced abundantly throughout the summer. The flowers are deep yellow and the petals, which have serrated margins, are edged with dark red-orange. The oval leaves grow to 8 inches in length and are green.
Winter-flowering - These kinds were obtained by hybridizing B. socotrana and B. Dregei. They have bronze-green leaves and a profusion of flowers during the winter. The flowers may be single or double and colored rose, carmine, scarlet, pink, and rosy-crimson.
All Begonias need light, well-drained soil that is neutral or slightly acidic. They need bright, but indirect sunlight. They need more water when they are growing actively, less when they are not. In late spring and early summer, they should be given fertilizer with every watering. They should be repotted every spring. Tuberous Begonias can be started in early spring by setting tubers into shallow flats. When Tuberous Begonias are about half and inch long, they can be potted into 4- or 5-inch pots filled with two parts fibrous loam, one part leaf mold or peat moss, half a part well-decayed manure, and a sprinkling of sand. One-quarter ounce of bone meal should be added to each quart of compost. Pat down the soil firmly but don't ram it down with a potting stick. When the roots fill the pots, they can be repotted into 6- to 8-inch pots. Those grown for their beautiful leaves don't need to be taken out of their pots at the end of their growing seasons.
PROPAGATION: Seeds may be sown in early spring in pots of finely sifted compost made up of loam, leaf mold or peat moss and sand. Scatter them on top and press them in but don't cover them with soil. Lay a sheet of glass over the pots and keep them in 60-degree temperatures. When the seedlings have formed two pairs of leaves, transplant them into larger pots. New plants can also be started from old leaves. Mature leaves are taken off the plants and placed underside downwards in sand and peat moss in a terrarium. When roots form, they are potted in small pots. Cuttings, 3-6 inches long, may be inserted into sand, in the spring or summer. These are placed in a warm propagator and kept closed until they have formed roots. They are then repotted into larger pots. Begonias that form rhizomes can be cut into several pieces in early spring and potted separately.
Cane-stemmed - B. Albopicta (Guinea-wing Begonia); B. corallina 'Lucerna'; B. 'Orpha C. Fox'; B. 'Orange Rubra'.
Rex-cultorum - B. 'Merry Christmas'; B. 'Duartei'; B. 'Helen Lewis'; B. 'Silver Queen'.
Rhizomatous - B. Manicata; B. pustulata 'Argentea'; B. masoniana; B . bowerae (Eyelash Begonia); B. manicata 'Crispa'; B. 'North Bedson'; B. 'Oliver Twist'; B. prismatocarpa; B. nelumbiifolia (Lily-pad Begonia).
Semperflorens - B. 'Red Ascot'; B. 'Organdy'.
Shrub-like - B. foliosa (Fern Begonia); B. olsoniae; B. scharffii; B. 'Weltoniensis'; B. 'Ingramii'; B. metallica; B. 'Thurstonii'; B. serratipetala.
Tuberous - B. 'Billie Langdon'; B. 'Roy Hartley'; B. 'Flamboyant'; B. 'Apricot Cascade'; B. 'Can-Can'; B. sutherlandii.