Begonia

Begonias are warm-season plants that should not be set outdoors until nighttime temperatures consistently remain above 50 degrees Fahrenheit. Choose a location with morning sun and afternoon shade, or dappled light throughout the day. Prepare beds with rich, well-drained soil amended with compost and peat moss to provide the moist, humus-rich conditions begonias prefer. Space wax begonias eight to twelve inches apart and tuberous types twelve to fifteen inches apart.

Water begonias consistently, keeping the soil evenly moist but never waterlogged. Water at the base of plants to keep foliage dry, as wet leaves are prone to powdery mildew and botrytis. Apply a balanced liquid fertilizer every two to three weeks during the growing season, or use a slow-release granular fertilizer at planting time.

Wax begonias are largely self-cleaning and require minimal deadheading. Tuberous begonias benefit from removing spent flowers and pinching off the two smaller female blooms flanking each large male flower to direct energy into the showiest blooms. In fall before frost, dig tuberous begonia tubers, dry them for a few days, and store in dry peat moss at 50 degrees Fahrenheit over winter.

Begonias belong to the family Begoniaceae and are native to tropical and subtropical regions across Central and South America, Africa, and southern Asia. The genus was first formally described in 1690 by the French botanist Charles Plumier, who encountered these plants during an expedition to the Caribbean islands, particularly in modern-day Haiti and the Dominican Republic. Plumier named the genus in honor of his patron Michel Begon, who had sponsored the botanical expedition as part of his broader efforts to catalog the natural resources of France's colonial territories.

The first begonia species to reach European gardens was Begonia nitida, which arrived in England around 1777. However, it was the discovery of the tuberous begonias of the Andes in the mid-19th century that truly ignited begonia mania among horticulturists. Plant hunters such as Richard Pearce collected Begonia boliviensis, B. pearcei, and B. veitchii from the cloud forests of Bolivia and Peru between 1864 and 1868, sending them back to the Veitch Nurseries in England. These Andean species became the foundation of the modern tuberous begonia hybrids that are grown worldwide today.

In the late 1800s, breeders in Belgium and England crossed these wild species to create the large-flowered, double-petaled tuberous hybrids that resemble roses and camellias. Belgium, particularly the city of Ghent, became the global center of begonia breeding, a tradition that continues to this day. Rex begonias, prized for their spectacular foliage, were developed from Begonia rex, discovered in Assam, India, in 1856. Meanwhile, wax begonias (Begonia semperflorens) became popular bedding plants due to their heat tolerance and continuous flowering. Today, begonias remain among the most popular ornamental plants worldwide, cultivated as houseplants, bedding plants, and container specimens across every inhabited continent.

Begonias require rich, well-drained soil with a pH of 5.5 to 6.5. They prefer soil high in organic matter, so amend beds generously with compost, peat moss, or leaf mold. In containers, use a premium peat-based potting mix with added perlite for drainage. Feed with a balanced liquid fertilizer every two to three weeks during the growing season. Tuberous begonias are heavier feeders than wax types and benefit from a high-potassium fertilizer as flowering begins to promote larger blooms.

Begonia flowers are primarily enjoyed in the garden and container displays rather than as cut flowers. However, tuberous begonia blooms can be floated in shallow bowls of water for elegant tabletop displays. Deadhead tuberous begonias by pinching off spent male flowers and the small female flowers on either side of the showy male bloom. Wax begonias are self-cleaning and rarely need deadheading. At season's end, dig tuberous begonia tubers before frost for winter storage.

Tuberous begonia tubers should be dug after the first light frost, when foliage begins to yellow. Allow the stems to dry and fall off naturally, then brush soil from tubers and cure in a warm, dry place for one to two weeks. Store in dry peat moss or vermiculite at 45 to 55 degrees Fahrenheit through winter. Check periodically for rot and discard affected tubers. Wax begonias can be potted up before frost and grown as houseplants on a bright windowsill through winter, returning them outdoors the following spring.