Culture
Best grown in rich, organic, well-drained soils in dappled sun or bright shade. Avoid full sun or full shade. Best in cool summers. Dislikes high heat and humidity. Can be tricky plants to grow well. Keep soils consistently moist through regular watering, but avoid over watering. Protect from strong winds, but provide good air circulation. Regular fertilization during the growing period produces most profuse bloom. Start plants indoors in late winter about 2 1/2 - 3 months before time to set out. Set outside only after all threat of frost is over. Plant tubers shallowly with concave side up. 3-4 tubers per hanging basket or space 12-18" apart in borders. Taper off watering in fall when leaves begin to turn yellow. Before first fall frost, store containers in frost free location or dig up tubers and store. If tubers are to be dug up, lift, shake off soil, dry and then cover with a dry medium such as perlite, vermiculite or peat. Store until time to replant in late winter in preparation for the next growing season. Container plants may be brought indoors in fall and grown as winter houseplants.
Noteworthy Characteristics
Begonia is a genus of about 1,300 species of annuals, perennials, shrubs and climbers. Most have fleshy stems. Some produce underground tubers or rhizomes. They are grown for their showy flower or colorful leaves; some for both. Begonias can be divided into 7 informal groups by growth habit: cane-like, rex-cultorum, rhizomatous, semperflorens, tuberous, trailing or scandent, thick-stemmed and shrub-like.
Tuberous begonias are characterized by their thickened tubers which are used to store water and nutrients during the winter dormant period. These cultivars are mainly grown for their showy flowers, which come in a wide range of sizes and colors including pink, red, orange, yellow, and white.
Genus name honors Michael Begon (1638-1710), Governor of French Canada.
Group name refers to the tuberous nature of these begonias.
Tuberosa Group, often called tuberous begonias, are a large and diverse group of tender, summer-flowering plants typically growing 12-18" tall and featuring brightly colored waxy-petaled flowers in colors ranging from white to yellow to apricot to pink to rose to red. Blooms from summer to fall. Hybrids are arranged into 13 different groups based upon such factors as flower shape (e.g., rose, camellia or carnation), petals (e.g., single, double, ruffled, banded) or habit (cascading, bushy). Pointed leaves to 8" long.
Problems
Watch for ealybugs, aphids, whiteflies, slugs and snails. Susceptible to powdery mildew, botrytis, and stem rot, especially in humid conditions with poor air circulation. Tubers may rot if soils kept too moist.
Uses
Suitable for use in hanging baskets, containers, or window boxes. Popular bedding annual for borders and edging. Can be grown as a houseplant.