The genus Begonia encompasses one of the largest groups of flowering plants, boasting over 2,000 different species and countless hybrids within the family Begoniaceae. These plants are valued for their showy, often colorful flowers and their diverse, ornamental foliage. The variety of begonias, ranging from tiny terrarium specimens to large shrubs, all share a common ancestry rooted in the world’s humid, warm regions. Understanding their native origins in tropical and subtropical climates is the first step to successfully growing these plants.
Global Habitat and Native Range
Begonias are naturally distributed across a broad, pantropical belt, primarily inhabiting the moist, forested regions of Central and South America, Africa, and Southern Asia. While the genus is globally widespread, Africa is sometimes considered the center of origin. These plants are found as understory inhabitants, growing on the forest floor, where they are protected from intense, direct sunlight.
Their natural environment dictates a preference for consistent warmth and high atmospheric moisture, which are hallmarks of tropical and subtropical zones. Begonias grow in the wild as terrestrial herbs in the soil, or as epiphytes, growing non-parasitically upon trees. They thrive in well-draining soil that is rich in organic matter, often with an acidic to neutral pH. This background explains why all cultivated begonias require shelter from cold, dry conditions and harsh sun exposure.
Growing Begonias Outdoors
For gardeners, the ability to grow begonias outdoors depends on local climate, specifically the USDA hardiness zone. As tender, tropical plants, begonias are only reliably perennial in frost-free zones, generally within USDA Zones 9 to 11. In these warm regions, they can remain in the ground year-round, often acting as evergreen shrubs or groundcovers.
In colder zones (Zone 8 and below), begonias are treated as seasonal annuals, providing color from spring until the first frost. They should only be planted outside once the danger of frost has completely passed and nighttime temperatures consistently remain above 50°F. Tuberous varieties must be dug up before frost, cured, and stored in a cool, dry place above 45°F to overwinter successfully.
Outdoor placement requires a microclimate that mimics their native forest floor, meaning a location that receives partial shade or filtered light. Most varieties will suffer leaf scorch if exposed to intense afternoon sun, though some wax begonia cultivars can tolerate more direct sun. The soil must be consistently moist but never soggy, demanding a well-drained mix that prevents root rot, which is a common issue.
Essential Conditions for Indoor Growth
Since most people live outside the perennial growing zones, cultivating begonias indoors is the most common method of enjoyment. Indoor growing requires creating an artificial environment that replicates the warmth and humidity of their native habitat.
Light
The primary necessity is bright, indirect light, which can often be found a few feet away from a sunny window or behind a sheer curtain. Direct sun coming through a window pane can easily burn the foliage, particularly on delicate types like Rex begonias.
Temperature
Maintaining a consistent temperature is important, with most begonias preferring a range between 65°F and 75°F. They are sensitive to sudden temperature fluctuations and should be kept away from cold drafts near windows or heat vents that can dry them out.
Humidity
Humidity is a particularly important factor, as the air inside modern homes is often much drier than these plants require. To boost the surrounding moisture, owners often employ a small room humidifier or place the potted plant on a pebble tray filled with water, ensuring the pot itself does not sit in the water. Rex begonias and other foliage-focused types can require humidity levels above 75%, making enclosed environments like terrariums ideal for their sustained growth. Consistent care in these three areas allows begonias to thrive indoors year-round, regardless of the climate outside.