The genus Begonia is one of the largest in the plant kingdom, encompassing over 2,000 species and thousands of hybrid cultivars, which explains the confusion about their proper placement. These plants originated in tropical and subtropical regions across the globe, giving them a wide range of natural habitats and growth habits. The answer to whether a begonia is an indoor or outdoor plant is truly “both,” as its suitability depends entirely on the specific type and the local climate conditions. Their incredible diversity means some varieties are grown as temporary bedding plants, while others are cultivated year-round as permanent houseplants.
Understanding the Major Begonia Groups
Begonias are broadly classified into groups based on their root structure or stem habit, which dictates their typical use in a garden or home. The largest group is the Rhizomatous Begonias, which includes the popular Rex Begonia types. These varieties grow from thick, horizontal stems, or rhizomes, that creep along the soil surface. They are prized almost exclusively for their highly decorative foliage, making them primarily indoor houseplants.
Tuberous Begonias grow from a specialized underground storage organ called a tuber. They are known for producing large, showy flowers in vibrant colors. This group naturally goes dormant in winter, making them a common choice for seasonal outdoor color in containers and hanging baskets in temperate climates.
The third major group is Cane Begonias, recognized by their upright, bamboo-like stems and often featuring distinct “angel wing” foliage. This versatile group can thrive either indoors as permanent houseplants or outdoors as seasonal accents, depending on the growing zone.
Essential Care for Outdoor Begonias
When grown outside, begonias are typically used as colorful bedding plants or container fillers during the warmer seasons, as most varieties are not frost-tolerant. The vast majority of begonias prefer a location that provides bright shade or filtered sunlight, mimicking their native forest understory habitat. Direct, intense afternoon sun, especially in hot climates, can easily scorch their leaves or cause the colorful foliage to fade.
The soil for outdoor begonias must be rich in organic matter, slightly acidic, and possess excellent drainage. Soggy soil is a common cause of failure, as it promotes root rot in both tuberous and fibrous-rooted types.
In regions that experience frost, gardeners treat most outdoor begonias as annuals. For Tuberous Begonias, this means reducing water in the late summer and lifting the tubers after the foliage naturally yellows and dies back, storing them in a cool, dry, frost-free location for the winter.
Key Requirements for Indoor Begonias
Growing begonias indoors, particularly the Rhizomatous and Cane types, centers on recreating a stable tropical environment. Indoor begonias require bright, indirect light to maintain the vibrancy of their foliage and encourage flowering. An east- or west-facing window works well, providing sufficient light without the harsh intensity of direct midday sun.
A major challenge indoors is providing the necessary humidity, as the optimal range for many begonias is 50% to 60%. Placing the potted plant on a shallow tray filled with pebbles and water can help elevate localized moisture around the foliage.
Proper watering indoors is achieved by letting the top inch of soil dry out completely before watering thoroughly. The plants are susceptible to root rot if the soil remains constantly saturated. Temperatures should be kept stable between 65 and 75 degrees Fahrenheit, avoiding cold drafts or proximity to heating vents.