Introduction: Begonias are mostly succulent herbs from the tropics.  Although tropical in origin, begonias are usually found in partially shaded, moist and humid locations, often at higher elevation.  Most can not tolerate high temperature, but grow best at moderate temperatures.  Begonias are monoecious dicots, producing both male and female flowers on the same plant.  The female flowers are noticeable for the three winged ovary at the base of  the petals whereas the male flowers usually have only two petals.  Seeds are very small.  There are over 1,000 species, mostly in the genus Begonia and 10,000 cultivated begonias.  The major groups include the fibrous-rooted, rhizomatous and tuberous-rooted begonias.  Many begonias are grown as outdoor ornamentals, but most are indoor plants and those commonly grown outdoors generally make attractive indoor plants. 
 Wax begonias, Begonia semperflorens, are very popular fibrous rooted begonias.  They have waxy leaves and flower freely.  Leaves may be green, bronze or red and flowers may be single or double in shades of red, pink, orange and white.  Wax begonias often do best in moderate to bright light in winter and partial shade in summer.  Many cultivars grown in cooler parts of the temperate zone thrive in bright light at cooler temperatures but new groups of cultivars have been developed for use in warmer climates and these grow well at higher temperatures and can tolerate higher light intensities at those temperatures
 Angel wing begonias have long, cane-like stems and leaves shaped like the wings of an angel.  Both standard and dwarf forms exist and many variegated and on-variegated leaf patterns and flower colors occur.  Flowers are usually produced in large, pendulous clusters.
 The beef steak begonia is an example of a rhizomatous begonia.  It has a heavy, succulent stem that grows just above the soil surface and sends out adventitious roots.  These begonias send flower stalks of many small flowers well above the foliage.  Many different leaf color patterns occur, the leaves have various shapes, leaf margins range from entire to deeply lobed and many have hairy leaves.
 Rex begnoias are mostly rhizomatous begonias.  Their main feature is foliage with many bright and unusual color patterns.  Their flowers are usually on very small stems and hidden be the leaves.  This group of begonias will grow in filtered light or indirect light and may burn if they are in direct light.
 Tuberous-rooted begonias are especially common in cooler parts of the temperate zone.  They produce large showy flowers on small upright or cascading plants.  Most require special care when grown in warmer areas.  Tuberous-rooted begonias often have a summer or winter rest period. 

General Care of Begonias:


temperature: Moderate temperature is best.  Some begonias prefer cool temperature. Most are forest floor plants but some have origin or adaptation to high elevation in the tropics, hence their preference for cool to moderate temperature.
medium: Media rich in organic matter are best for most begonias.  The potting medium could be peat or compost or a mixture of peat or compost with sand or other ingredients.
water: Begonias should be kept moist and for many the medium should be allowed to dry between  waterings.  Although some will tolerate having wet soil, most do not.  Avoid water with high salt content, especially sodium, as this will burn the plants and damage the very fine roots.
light: Moderate light is best for most begonias though many tolerate low light.  Bright light would damage most begonias, though it does not burn many cultivars of wax begonia.
fertilization: The aroids respond to fertilizer.  Large leaves are the result of ample fertilizer.  A fertilizer higher in nitrogen than phosphorus and potassium is common. The roots of begonias are especially sensitive to salts.  Careful application of inorganic fertilizer is essential.  Most thrive with fertilizers containing a little more nitrogen than phosphorus or potassium, but those grown for heavy displays of flowers need a fertilizer with adequate amounts of nitrogen, phosphorus and potassium.  Since begonias are grown in media high in organic matter, their nutrients can be derived from organic matter.
humidity: Most begonias thrive at higher humidity, producing larger leaves and less marginal burning of the leaves.
pests and problems: Begonias are relatively pest free, though pests such as mealy bugs may become numerous and should be treated.
grooming: Keep yellowing and dead leaves trimmed off.  Make cuttings of long stemmed types to reduce their legginess.  Remove spent flowers.
propagation: Seed and stem cuttings are very common, and leaf and leaf section cuttings are also used.


Virtual Garden's Directory of Flowering House Plants