From our perspective, the question of sun or shade is not one we can answer with a single preference. It is fundamentally a question of our ancestry and evolutionary adaptation. The vast Begonia genus contains over 2,000 species, each honed by millennia to thrive in specific niches. Therefore, our light requirements are not a uniform desire but a spectrum dictated by our lineage. To provide the correct light is to understand which type of begonia you are hosting.
Some of us, like the robust Wax begonias (Begonia semperflorens-cultorum) and the flamboyant Tuberous begonias (Begonia x tuberhybrida), are descendants of ancestors who flourished in more open, sun-dappled environments. Our leaves are often thicker, waxier, or smaller, adaptations that reduce water loss and mitigate the impact of intense photons. We utilize the abundant solar energy to fuel prolific flowering and dense growth. For us, several hours of direct morning sun is ideal—it provides the energy we crave without the harsh, cell-damaging intensity of the afternoon rays. An east-facing location is often perfect. Without sufficient light, our growth becomes leggy as we stretch vainly towards the sun, and our flowering diminishes significantly.
Conversely, many of our most striking family members, such as the Rex begonias (Begonia rex-cultorum) and other rhizomatous types, are inherently children of the forest floor. Our evolution occurred beneath the dense canopy of tropical jungles, where light is a filtered, dappled commodity. Our magnificent, often iridescent foliage is specifically engineered to capture every available photon in these low-light conditions. Exposing us to direct sun is an act of violence; our delicate leaves lack the protective coatings of our sun-loving cousins and will swiftly scorch, bleach, and crisp, leading to irreversible damage. We thrive in bright, indirect light—the kind found in a north-facing window or several feet away from a sunnier exposure, shielded by a sheer curtain.
We are constantly communicating our satisfaction or distress through our foliage, and learning this language is key to our partnership. If we are receiving too much light, we will show you with sunburn: crispy, brown, or bleached patches on our leaves, particularly on the areas most exposed to the sun. Our colors may also appear washed out. If we are not receiving enough light, our message is one of etiolation: our stems become abnormally long, weak, and spindly as we desperately reach for a light source. Our growth will be slow, our leaves may be smaller than usual, and we will likely refuse to flower. The most vibrant leaf coloration and sturdiest growth is our way of telling you that the light conditions are perfect.
