Begonia is a large genus in the Begoniaceae family with many tuberous or rhizomatous species. Probably this genus is best known for its showy tuberous hybrids that are summer growers, tender, and dormant in winter.
Begonia boliviensis is a tuberous species native to Bolivia. It has small orange-red flowers and can be grown as a pot plant. They do best in part sun and blooms prolifically during mediterranean-type summers if planted in the ground where they can reach 2-3ft (<1 meter) tall. Propagation is easy by cuttings. If cutting is taken during summer, it will form a thumb sized tuber by winter and will go deciduous like adult plants and return in late spring. Photos 1-3 are by Mary Sue Ittner of plants blooming summer 2004 in the Mendocino Coast Botanical Gardens and of a seed pod of her own plant a year later. Photo #4 was taken by Nhu Nguyen. The last photo was contributed by the UC Botanical Garden.
Begonia grandis is a tuberous species native to China and Japan and is among the most cold hardy. A common synonym is Begonia evansiana. It blooms in late summer and autumn and does an outstanding job of propagating itself by seed and bulbils formed in the leaf axils. The bulbils appear at the end of the season as the plants lose their leaves and are 3-4mm in size. The first photo below is from Wayne Crist who photographed it in his garden in early September. The companion plants include blue Lobelia syphilitica and yellow Solidago rugosa 'Fireworks'; the dash of red is from Lobelia cardinalis (the real thing, not the garden plants sometimes given that name). The second and third photos are of the typical medium pink form taken August 2004 by Jay Yourch. The fourth photo by David Pilling is of bulbils.
Photos of a white or very pale pink form taken August 2004 by Jay Yourch.
Begonia × tuberhybrida 'Nonstop' is an F1 hyrbid seed strain introduced by the German seed company Ernst Benary in 1972. They feature bright big flowers on small robust plants. Seed is dust like, sown in February it will produce flowering plants by August. In the photographs below by David Pilling notice the difference between the (double) male and (single) female flowers. Leaf cuttings can be used to produce more plants. Tubers are dug up and stored frost free through the Winter.
Photographs of seed on a 1mm grid, in the second image the grid lines are just visible at left and right.
Begonia sutherlandii, from KwaZulu-Natal, South Africa, is precariously hardy in the Washington, D.C. area. Here it is seen in the garden of Wayne Crist in North Bethesda, Maryland. This species grows from tubers and forms little tubers in the leaf axils.
