Rex begonias

A form of rhizomatous begonia, these plants are often grown for show and for their attractive multi-coloured leaves, which appear in a variety of shapes and sizes. They are sometimes referred to as the painted-leaf begonia.

Description
Rex begonias have heart-shaped leaves that appear in many colours, including red, green and silver. The surface of these leaves may be pimpled or rippled and the leaves can grow up to 46cm in width. Hybridisation of these plants has led to additional colour and size options.

Habitat
Rex begonias originate from the tropics of Asia and India and are believed to require a humidity of around 69% to prosper, which can pose a problem to gardeners keen to grow their own crop of this particular plant. Rex begonias thrive in tropical conditions, where they can use the canopy of other plants as shade. These wild rex begonias live in particularly dense areas of forest. Within these places, their preferred conditions are foggy air, laden with moisture.

Availability
Rex begonias grow well when placed in aerated soil that is rich with nutrients. Their preferred environment includes plenty of humidity and these plants will grow best when conditions are as close as possible to those found in the forest.

Species
Although the rex begonias are a species of begonia on its own, a number of cultivars exist for this plant. These include a breed known as fireworks, so called because of the black ‘burst’ shape on their leaves, which come in purple and metallic shades.

Care Tips
Rex begonias work best when kept reasonably moist and warm, whatever the season. During the spring and summer, use liquid fertiliser once per fortnight, but reduce your watering in winter. Over-watering or fertilising can damage a rex begonia. The amount of light the plant receives matters too; avoid direct sunlight and try to filter the light to achieve the desired foliage.

Did You Know?
Leaf shine can have an adverse effect on a rex begonia, so be careful. To ensure a plant grows upwards, regularly move the plant pot to reflect the movement of the sun.

References
http://www.finegardening.com/design/articles/rex-begonia-varieties.aspx
http://www.plant-care.com/rex-begonias-showiest-foliage-plants.html
http://www.national-begonia-society.co.uk/Species%20&%20Hybrids/JR%20Species%20-%20Rex.htm
http://www.guide-to-houseplants.com/rex-begonia.html