Begonia

Begonia is a member of the Begonia family (Begoniaceae) and is native to the Tropics and Subtropics of Central and South America, Africa and Asia. They are found as forest understory plants in their native habitats. They are grown as houseplants, herbaceous perennials or annual bedding plants. The name, Begonia, honors Michael Begon (1638-1710),  who was the Governor of French Canada.  

Begonias may be upright and mounding while some are perfect for hanging baskets due to their trailing or spreading habit.The size of the mature begonia can vary from a few inches to over 12 feet tall, but most begonias will be 8 inches to 2 feet tall. There is a wide variety of flower and foliage colors. The flowers can be single or double and are found in colors of pink, red, orange, yellow and white. The leaves also have varying size, shape and texture, but are usually asymmetrical, at least at the base. They may be heart-shaped, star-shaped or round, and can be found in colors of green, brown, bronze or burgundy. Some have variegated leaves while others may have fuzzy hairy textures.

With more than 2100 species, the genus Begonia is ranked 8th on the list of largest genera of flowering plants as of 2023. Growers recognize several informal types of species and hybrids, based on the growth habits of the plants. They include the following:

• Wax Begonias:  Semperflorens hybrids or wax begonias are small, fibrous-rooted plants with an endless profusion of small flowers. These are usually grown as annual bedding plants. Includes the species Begonia cucullata var. cucullata.  
• Tuberous Begonias: Tuberous begonias are often grown for their large, showy flowers. The popular Begonia boliviensis and its hybrids are in this category. Some tuberous begonias have showy foliage. 
• Cane Begonias: Cane begonias have upright stems and are up to 6 feet tall, and often lose their lower leaves and resemble canes. The foliage may be showy, and they often bear clusters of flowers at the tips of the stems. The species Begonia maculata, and the popular Angel Wing begonia are in this category.
• Rhizomatous Begonias:  Rhizomatous begonias, as the name suggests, grow from a creeping stem or rhizome. They have showy foliage and flowers borne on erect stalks above the leaves. This type includes the species Begonia masoniana and Begonia cleopatrae.
• Rex Begonias:  Rex begonias are a subgroup of the Rhizomatous begonias. There are hundreds of hybrids in this group derived from Begonia rex. They are grown for their colorful foliage. These plants require humidity above 75% and decline if the humidity is too low. They make excellent terrarium plants. 

Most commonly cultivated begonias prefer partial shade and a humid environment. They do not tolerate cold temperatures below 55 degrees Fahrenheit. They will thrive in moist, well-drained soil with high organic matter and an acidic to neutral pH between 5.5 to 6.5. Tall varieties may need to be staked for support. The leaves and flowers are very fragile and should be protected from high winds. Begonias may be propagated by seeds, stem cuttings, leaf cuttings or division.

Begonias may be used as houseplants, bedding plants, container plants, window boxes or hanging baskets. Their bright flower colors will brighten your home or landscape.

Insects, Diseases, and Other Plant Problems: Monitor for mealybugs, whiteflies, thrips, scales, snails, slugs and spider mites. Avoid overwatering because begonias are highly susceptible to root rot. Fungal leaf diseases such as powdery mildew can develop. It is best practice to water the plant at the base and avoid the leaves. Botrytis blight and stem rot and Pythium root and stem rot can occur. 

VIDEO Created by Elisabeth Meyer for "Annuals, Perennials, Vines, and Groundcovers" a plant identification course offered in partnership with Longwood Gardens.