Begonia (Begonia spp.)

One of the most diverse genera in the plant world — begonias offer spectacular foliage, vivid blooms, and surprisingly easy care once you understand their one rule about water.

By Plant Care DB Team · Updated June 8, 2026

💧 Watering calculator

Water your Begonia about every 10 days. Always check that the top inch of soil is dry first — when in doubt, wait.

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What is a begonia, and why are there so many kinds?

Begonia is a genus of more than 2,000 species — one of the largest genera of flowering plants on earth — native to tropical and subtropical regions across Africa, Asia, and the Americas. They range from thumbnail-sized terrarium plants to shrubs several feet tall, and their diversity of leaf shapes, textures, and colors is staggering. Indoors, begonias are broadly grouped by growth habit into a handful of popular types: cane begonias (upright stems with bamboo-like nodes, e.g., B. maculata), rex begonias (grown primarily for spectacular patterned foliage), rhizomatous begonias (spreading from a creeping rhizome), and wax begonias (compact, free-flowering, often used outdoors but excellent on a windowsill). Understanding which group your plant belongs to is the fastest shortcut to caring for it well.

What light does a begonia need indoors?

The genus-wide rule is bright, indirect light — think a few feet back from a south- or west-facing window, or directly in an east- or north-facing one. Cane types like ‘Wightii’ or Begonia maculata are the most sun-tolerant and enjoy a couple of hours of gentle morning sun, which intensifies their spots and encourages heavier flowering. Rex begonias, with their thin, elaborately patterned leaves, prefer consistent bright shade — direct sun bleaches and scorches their delicate surfaces. As a genus-level rule: if you can comfortably read a book by the available daylight, your begonia is probably getting enough light.

How should you water a begonia to avoid root rot?

Water is where most beginners go wrong. Begonias need consistently moist but never soggy soil; their fibrous or rhizomatous roots are highly susceptible to rot if kept wet. Let the top inch or two of the mix dry out between drinks, then water thoroughly until it drains from the bottom — and empty the saucer within 30 minutes. Never let the pot sit in standing water. Use a fast-draining mix (a standard potting mix lightened with perlite works well) and a pot with good drainage holes. If in doubt, wait one more day: a slightly underwatered begonia recovers quickly; an overwatered one often doesn’t.

A few standout categories and names worth knowing:

Are begonias toxic to cats and dogs?

Yes — the ASPCA lists Begonia spp. as toxic to cats, dogs, and horses. The toxic principle is soluble calcium oxalates, which cause oral irritation, excessive drooling, vomiting, and difficulty swallowing if the plant is chewed or ingested. The ASPCA specifically notes the underground portions (tubers, in tuberous types) are the most concentrated source of the compound, but all parts of the plant should be considered unsafe. Keep begonias on high shelves or in rooms pets cannot access.

How do you pick a healthy begonia at the garden center?

Look for a plant that is stocky, not leggy — compact stems with leaves spaced closely together indicate it has been grown in adequate light. Check the undersides of leaves for spider mites (fine webbing, tiny moving dots) and the soil surface for fungus gnats (small flies that lift off when you disturb the pot). Skip any plant with yellowing lower leaves or a sour-smelling, sodden potting mix, both signs of overwatering stress. For rex and rhizomatous types, choose one where new leaves are already unfurling — a plant actively growing at purchase will settle into a new home much faster than one that is dormant or stressed.

Frequently asked questions

How often should I water a begonia indoors?

Roughly every 1–2 weeks — water when the top inch of soil feels dry but before the mix dries out completely. Begonias are very sensitive to overwatering; soggy roots rot quickly. Always let the pot drain and never leave it sitting in water.

Do begonias need a lot of light indoors?

Bright, indirect light is the sweet spot for most indoor types. Cane begonias (like Maculata) tolerate a bit of gentle morning sun; rex begonias prefer steady bright shade. Avoid direct afternoon sun — it scorches the foliage — and avoid deep shade, which reduces flowering and stretches stems.

Are begonias toxic to cats and dogs?

Yes. The ASPCA lists Begonia spp. as toxic to cats, dogs, and horses. The most toxic part is underground (the tubers), but all parts contain soluble calcium oxalates, which cause oral irritation, drooling, vomiting, and difficulty swallowing if chewed. Keep begonias out of reach of pets.

How do I get my begonia to bloom again?

Give it the brightest indirect light you can, feed with a balanced or low-nitrogen fertilizer every two to four weeks during the growing season, and make sure it's not rootbound. Many begonias also respond to slightly cooler nights (around 60°F/16°C) as a bloom trigger.

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