Genus Begoniaincludes 1,500 species and more than 15,000 hybrids and cultivars with a tremendous variety of habits, foliage and blooms. There are upright, trailing, hanging and climbing begonias. A few species and horticultural varieties are commonly grown as houseplants. Several new hybrids that are compact prolific bloomers are grown as annuals in northern gardens.
Cane-stemmed begonias have upright, bamboo-like stems with nodes, and asymmetrical leaves often marked with silver. These old-fashioned begonias are also called angel-wing begonias. There are numerous modern excellent blooming hybrids, including B. 'Lucerna', B. 'Sophie Cecile' and polka-dot begonia (B. maculata).
Rhizomatous begonias grow from a creeping rhizome. They are compact good bloomers. Their leaves come in a wide variety of shapes, textures and colours, from miniature to giant, round or star-shaped, hairy, puckered or smooth, plain green or mottled in various shades of brown. Examples: 'Iron cross' begonia (B. masoniana), castor bean begonia (B. 'Ricinifolia'), beefsteak begonia (B. 'Erythrophylla').
Rex begonias have distinctive decorative wing-, star- or heart-shaped foliage in bright hues of green, pink, burgundy, brown and silver. Examples: Begonia 'Silver Queen', Begonia 'Venetian Red', Begonia 'Escargot'.