With 1,500 named begonia species, plus thousands of hybrids, it can be hard to draw generalizations about growing begonias. This profile is dedicated to only the broadest of rules governing the cultivation of the begonia genus, which includes plants that can be grown as upright specimens, trailing plants, or even delicate greenhouse plants. Begonias are grown for their foliage and flowers and include upright shrubs and rhizomatous plants. For more specific information on your particular type of begonia, see one of the specific profile pages associated with that type of begonia.
Light: Most begonias will do well in moderate, bright but not direct sunlight. Winter-blooming varieties benefit from additional light during the winter months to induce flowering.
Water: Begonias enjoy the same gentle conditions sought by fern growers. They like even water, but hate being overwatered, and thrive on humidity, but don't like misting.
Temperature: No begonias can tolerate freezing temperatures.
Soil: Airy, light, fast-draining soil.
Fertilizer: Use liquid fertilizer weekly at quarter strength or biweekly at half strength. You can use high-phosphorous fertilizer for blooming varieties.
The vast majority of begonias offered in the trade are hybrids and thus cannot be accurately propagated from seed, but don't worry: begonias are popular in part because they are very easy to propagate. Rhizomatous begonias can be easily propagated by rhizome division, while almost all begonia species will readily sprout from leaf-tip cuttings. A rooting hormone
can help them sprout. If you're taking cuttings of summer begonias with the purpose of over-wintering your plants indoors before moving them back out, make sure to take cuttings when the summer is still warm and humid so the cuttings will readily root.
Begonias should be repotted annually
, but the type of pot depends on the variety. Deep, fibrous-rooted begonias such as angel wing begonias should be repotted when they threaten to become too heavy or large for their pots, but keep in mind they benefit from being slightly underpotted. Rhizomatous begonias grow from a shallow, thick rhizome just under the surface of the soil and benefit from a wider, shallow pot that allows room for the rhizome to spread. As a general rule, begonias frequently do better in slightly smaller pots, since they are less likely to become waterlogged and the smaller pots stimulate blooms.
With thousands of begonias to choose from, it's impossible to list all the varieties here. Instead, growers frequently separate begonias into groups depending on their structure: cane type, rhizomatous, tuberous, Rex, Semperflorens, trailing, and shrub type. Begonia varieties are prized for their flowers (frequently pendant and borne in great clusters) or leaf types. Begonia leaves are available in a variety of shapes, from round and smooth to jagged, loped and hairy. Similarly, they range in size from miniature to giant. Varieties are explained in greater depth individually throughout this series of articles.
If you can grow a healthy fern indoors, you can likely grow a healthy begonia, which frequently have similar requirements as ferns. Nevertheless, if possible you should identify your particular type. Some begonias, such as the Rex varieties, can be difficult to grow well outside of greenhouses, while others are robust plants that frequently bloom well indoors. No matter the type, it's worth nothing that begonias frequently don't like to be moved or experience any change in conditions. Thus, if you have to move your plants, try to do it as gradually and gently as possible to reduce the risk of shock.