Why Begonia Type Is the Only Thing That Matters
Most houseplant care guides treat begonias as a single plant and offer a single light recommendation. This is the source of most begonia failures indoors. The genus Begonia contains more than 2,000 species, and the common indoor types have been selected and hybridized for traits that are almost mutually exclusive. Rex begonias are grown almost entirely for their patterned, metallic, jewel-toned foliage. Wax begonias are flowering machines that were developed for outdoor beds in full sun. Cane begonias shoot upward toward windows and need real light to bloom. Rhizomatous begonias creep horizontally and tolerate low-light conditions that most flowering plants refuse.
There is a simple mental model that makes this easier. Foliage begonias prefer lower indirect light; bloom begonias need more. Rex begonias are the clearest foliage type. Wax, cane, and tuberous begonias are the clear bloom types. Rhizomatous begonias sit in the middle, grown mainly for foliage with occasional flowers. Once you know which category your begonia belongs to, the right window becomes obvious.
Cane and Angel Wing Begonias: Light to Bloom
Cane begonias, which include the popular angel wing varieties, are among the most light-demanding begonias you are likely to keep indoors. They grow upright on bamboo-like cane stems, sometimes reaching a meter or more in height, and they produce large hanging clusters of flowers in pink, red, orange, or white. Those flower clusters are the whole point. Without enough light, cane begonias grow plenty of foliage but simply do not flower.
Cane begonias thrive at 2,500 to 5,000 lux. An east or west window on or close to the sill delivers this range reliably. A south window works well if there is some filtering or if the plant is set back slightly to avoid the most intense midday exposure. These begonias can handle a few hours of direct morning sun without issue, and that gentle early sun actually stimulates flowering. What they cannot handle is harsh afternoon direct sun in summer, which scorches the spotted silver foliage that makes angel wings attractive.
If your cane begonia grows vigorously but produces no flowers, insufficient light is almost always the cause. Move it closer to a brighter window and flowering usually follows within four to six weeks of the growing season.
Rex Begonias: The Type Most Killed by Too Much Sun
Rex begonias are the exception to almost every piece of begonia advice you will read. While most houseplant guides push people toward brighter windows, rex begonias need to go in the opposite direction. These are foliage plants with enormous, asymmetrical leaves covered in spiral patterns, metallic sheens, and colors ranging from silver-gray to burgundy, deep purple, and iridescent green. The spectacular leaves are the entire attraction. Flowers are small, infrequent, and often removed so the plant can direct energy into foliage.
Rex begonias are adapted to the forest floor. Their large leaf area is designed to capture diffuse ambient light, not direct sun. At 1,000 to 2,500 lux, which is what you get in a north or east window away from direct sun, they are in their element. Direct sun exposure produces bleached, pale, or silvery burn patches on the leaf surface within a matter of hours. The damage is immediate and permanent on that leaf. A rex placed in a west or south window without filtering is one of the most reliable ways to ruin an expensive plant quickly.
An east window is the go-to placement for rex begonias. Morning light is gentle, the plant never sees harsh direct sun, and the indirect brightness through the rest of the day keeps the foliage healthy and vibrant. A north window works if it is bright enough (800 to 1,500 lux at the windowsill) and the plant is positioned close to the glass. Keep rex begonias away from south and west windows unless a thick sheer curtain blocks the direct sun entirely.
Wax Begonias: The Sun-Tolerant Outlier
Wax begonias, also called semperflorens begonias, are the most sun-tolerant begonias sold as houseplants. They are the type planted by the millions in outdoor beds, window boxes, and containers in full sun. Indoors, a south-facing window with direct sun is genuinely good for them, not just tolerated but preferred.
These compact plants with waxy green or bronze leaves and continuous small flowers in red, pink, or white want 3,000 to 10,000 lux. At the higher end of that range, with several hours of direct sun, they bloom almost without pause. Below 2,000 lux they grow leggy and flower sparsely. Below 1,000 lux they struggle to maintain their compact shape and produce almost no flowers.
If you have a bright south window that you have been trying to find a plant for, wax begonias are one of the best indoor choices. The bronze-leafed varieties are especially sun-tolerant and add color contrast alongside their prolific flowers. The main care issue at a very bright south window is not light but water: the soil dries out faster and the plant wilts if you fall behind on watering.
Rhizomatous Begonias: The Middle Ground
Rhizomatous begonias grow from a thick horizontal stem (the rhizome) that creeps along the soil surface. They tend to be low and spreading rather than upright, with interesting textured, hairy, or deeply cut foliage. Many have attractive leaf markings and some produce sprays of small flowers in spring, but they are primarily kept as foliage plants.
Light needs sit comfortably in the moderate range: 1,500 to 3,000 lux. An east window is ideal. A north window with a bright exposure (close to the glass and with no obstructions) can work for the most tolerant varieties. South or west windows are fine as long as the direct sun is filtered or the plant sits far enough back that the beam does not hit the leaves.
Rhizomatous begonias are more tolerant of variable conditions than rex or cane types, which makes them a good option for people who have one moderately bright window and want a low-maintenance foliage plant with some personality.
Tuberous Begonias: Bright Indirect, No Harsh Sun
Tuberous begonias produce some of the showiest flowers in the begonia world, with large rose-like blooms in vivid pinks, oranges, reds, and whites. They are often grown in hanging baskets or as summer patio plants, but indoor tuberous begonias follow the same light logic: bright indirect light without harsh direct sun.
Target 2,000 to 4,000 lux. An east window or a filtered west window works well. These begonias do not tolerate the level of direct sun that wax begonias accept, and harsh exposure causes the petals to bleach and the leaves to scorch. At the same time, insufficient light reduces flowering significantly. Position them close to a window that receives bright indirect light for most of the day, with possibly an hour of gentle morning sun through an east window.
Lux Quick Reference by Type
Cane and angel wing begonias: 2,500 to 5,000 lux. East or west sill. Tolerate some gentle direct morning sun.
Rex begonias: 1,000 to 2,500 lux. East window or bright north window. No direct sun.
Wax begonias (semperflorens): 3,000 to 10,000 lux. South or west window, including direct sun, is ideal.
Rhizomatous begonias: 1,500 to 3,000 lux. East window. Tolerant of moderate variation.
Tuberous begonias: 2,000 to 4,000 lux. East or filtered west window. Avoid harsh direct sun.
Common Mistakes and What They Look Like
The most frequent mistake is placing a rex begonia in a bright window because "begonias like light." Rex begonias placed in direct or near-direct sun develop pale, bleached patches or silvery discoloration on the leaf surface. The leaf does not recover. If you notice this on a rex, move it immediately to a north or east window away from direct sun and the new leaves will grow undamaged.
The second common mistake is placing cane or wax begonias in a shaded corner because "they are tropical plants that like shade." Neither type is a shade plant. Cane begonias in insufficient light produce only foliage and never flower. Wax begonias in low light grow tall and floppy rather than compact and bushy, and flower very sparsely if at all. Both types need a real window, not a dim shelf.
Seasonal changes catch people out too. A window that gives bright indirect light in summer may drop to borderline levels in winter as the sun angle changes and days shorten. Begonias that bloom all summer sometimes stall in winter not because of temperature or watering changes but because the light level has dropped by 40 to 60 percent. Moving the plant closer to the glass, or adding a small grow light supplement during the shortest months, resolves this.
FAQ
How much light do begonias need indoors?
It depends on the type. Wax and cane begonias tolerate the most light and can handle several hours of direct sun. Rex begonias prefer lower indirect light around 1,000 to 2,500 lux and are damaged by direct sun. Rhizomatous begonias do well at moderate indirect light in an east window. Tuberous begonias want bright indirect light without harsh direct exposure. Knowing your begonia type is the most important step before choosing a window.
Why is my rex begonia getting bleached or pale patches?
Direct sunlight is almost certainly the cause. Rex begonias have large, thin leaves with rich pigmentation that is extremely sensitive to direct sun. Even an hour of harsh direct sun produces pale, bleached, or silvery patches that do not recover on that leaf. Move the plant back from the window or filter the light with a sheer curtain. An east window with morning indirect light is the safest placement.
Why is my cane begonia not blooming?
Insufficient light is the most common reason cane and angel wing begonias fail to flower indoors. These begonias need 2,500 to 5,000 lux for consistent blooming. A bright east or west window on or close to the sill is usually the minimum. Plants placed farther back in a room, or in north-facing windows, will grow foliage but rarely produce flower clusters. Moving the plant to a brighter window is usually enough to trigger blooming within a few weeks.
Can wax begonias grow in full sun indoors?
Yes, wax begonias (semperflorens) are the most sun-tolerant begonias and are widely used as outdoor bedding plants. Indoors, a south-facing window with direct sun is actually beneficial for them. They bloom most prolifically with several hours of direct sun each day. The bronze-leafed wax begonia varieties are particularly sun-tolerant. Even so, watch for wilting in very intense summer heat, which signals that the soil is drying out too quickly rather than too much light.
Which begonia type is best for a north-facing window?
Rex begonias and rhizomatous begonias are the two groups that manage best in lower-light north windows. Rex begonias actively prefer indirect light and can sustain themselves at 800 to 2,000 lux, which is typical of a well-placed north window. Rhizomatous begonias also tolerate lower light and prioritize foliage over flowers, making them well-suited to dimmer conditions. Avoid placing cane, wax, or tuberous begonias in north windows as they will grow poorly and not flower.