Houseplant · Begoniaceae
Polka Dot Begonia
Begonia maculata
Give it bright indirect light, careful watering, and humid air, and the polka dot begonia rewards you with spotted, silver-flecked leaves.
Bright indirect
USDA 10–11
2–3 ft · 0.6–0.9 m
Overview
The polka dot begonia earns its name the moment you see it. Long, angel-wing leaves are scattered with silvery-white spots and flip over to a deep crimson-red underside, all carried on upright, bamboo-like canes. It belongs to the cane-stemmed begonias and comes originally from the forests of southeast Brazil.
Grown indoors, it stays a manageable houseplant, reaching about 2 to 3 feet (61 to 91 cm) tall over a few seasons. Pendulous clusters of pale pink to white flowers appear in the warmer months, a quiet bonus on top of the foliage that draws most people in. It carries a moderate reputation: not fussy, but it does have a couple of firm preferences.
Those preferences come down to water and air. The plant hates wet feet and rots fast if the soil stays soggy, yet it still wants the high humidity of its native understory. Get the balance right, with steady moisture and air moving around the leaves, and it grows fuller and brighter year after year.
Care
The short version: bright indirect light, water only once the top of the soil dries, and keep the air humid but moving. Feed lightly through the growing season and pinch the tips to keep it bushy.
Light
Give it bright, indirect light near a window that never throws direct sun onto the leaves. It will get by in medium light or partial shade, but the spots fade and the canes stretch. Harsh midday sun scorches the foliage.
Water
Water moderately while the plant is growing, then let the top of the soil dry before you water again. This begonia rots easily, so the cardinal rule is never to leave it sitting in soggy soil or standing water. Back off in winter when growth slows.
Soil
Use a light, well-drained mix rich in organic matter, the kind that holds some moisture but drains fast. A slightly acidic pH of 5.5 to 6.5 suits it best. Good drainage is the single most important thing you can give it.
Temperature
Keep it warm, never letting the room drop below 55°F (13°C). Cold drafts and chilly windowsills make it shed leaves, so move it away from doors and vents in winter.
Humidity
This plant wants high humidity, more than most homes offer, so a humidifier or a pebble tray helps. The catch is that humid, still air invites powdery mildew, so pair the moisture with steady airflow around the leaves.
Feeding
Feed through the growing season, from spring into summer, with a balanced liquid fertilizer at alternate waterings, roughly every two weeks. Stop feeding in autumn and winter while the plant rests.
Pruning
Pinch the growing tips to push out side branches and keep the plant full instead of leggy. Regular pinching also holds its size in check and stops the lower canes from going bare.
Repotting
Repot every one to two years, or sooner if roots push through the drainage holes and water runs straight through. When you do, keep the dug-up roots and tubers away from pets, since they hold the most toxin.
Size & spacing
Indoors it reaches about 2 to 3 feet (61 to 91 cm) tall and spreads 1 to 2 feet (30 to 60 cm) wide. Give it space and airflow on all sides to keep mildew at bay.
Troubleshooting
Almost everything that goes wrong with a polka dot begonia traces back to water or air. Read the leaves and stems early and you can fix most of it before it spreads. Match what you see below, then act while the plant can still bounce back.
Wilting plant with a soft, blackened stem base
When the stem base turns soft and dark while the soil stays soggy, you're looking at root and stem rot from too much water. It's the most serious thing that goes wrong with this plant. Tip it out, cut away every rotted root and stem, and repot into fresh, fast-draining mix. From then on, water only once the soil surface has dried.
Fix:
- Remove the plant and cut away rotted roots and stems
- Repot into fresh, well-drained mix
- Water only after the top of the soil dries
White dusty film spreading across the leaves
That white, dusty coating is powdery mildew, a fungus that takes hold when humid air sits still around the plant. Open up the space so air can move, pull off the worst leaves, and keep water off the foliage when you water. The begonia wants high humidity, so airflow is what keeps that humidity from turning against it.
Fix:
- Improve air circulation around the plant
- Remove and discard affected leaves
- Avoid wetting the foliage when watering
Leaves yellowing and falling off
Overwatering is the usual reason leaves yellow and drop, especially when the soil never gets a chance to dry out. Cold is the other trigger, since anything below 55°F (13°C) or a steady draft will make a begonia shed. Let the top of the soil dry before you water again, keep the plant warm and out of cold air, and make sure the pot drains freely.
Fix:
- Let the top of the soil dry before watering again
- Move away from cold drafts and keep above 55°F (13°C)
- Ensure the pot drains freely
Cottony clusters, sticky leaves, or fine webbing
Several sap-sucking pests go after this begonia, and the clue is in what you see. White cottony clumps mean mealybugs, clouds of tiny white flies mean whiteflies, fine webbing with speckled leaves points to spider mites, and silvery scarring is the work of thrips. Pull the plant away from the rest of your collection, wash off what you can see, then treat with insecticidal soap or horticultural oil and repeat until they're gone.
Fix:
- Isolate the affected plant
- Wipe off or wash off visible pests
- Treat with insecticidal soap or horticultural oil and repeat as needed
Tall bare canes with leaves only at the tips
A begonia stretches and goes leggy when it sits in light that's too dim, and the problem gets worse if the growing tips are never pinched. Move it somewhere brighter, then pinch the tips to push out side branches. You can also cut a long cane back to a node, and it will break into fuller, bushier growth.
Fix:
- Move to brighter indirect light
- Pinch the growing tips to force branching
- Prune back leggy canes to a node to encourage bushier regrowth
Toxicity
This is a plant to keep away from pets and grazing animals. Every part holds calcium oxalate crystals, and the tubers and roots underground hold the most, so a chewed leaf stings the mouth and a dug-up root does worse. No part is edible, so keep it out of reach of small children too.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Moderate
A cat that chews any part of the plant gets a mouthful of calcium oxalate crystals, so expect drooling, pawing at the mouth, and vomiting. The tubers are the most concentrated, so keep repotting debris out of reach.
Dogs Moderate
Dogs react much the same way, with drooling and an upset stomach after a bite of leaf or stem. A dog that digs up and chews the roots can get a stronger dose.
Horses Moderate
The same oxalates trouble horses and other grazing animals, bringing on mouth irritation and stomach upset. Larger or repeated mouthfuls can strain the kidneys.
Rabbits Caution
The oxalate crystals that bother cats and dogs would irritate a rabbit's mouth and gut just the same, so treat the whole plant as off the menu.
Livestock Caution
Grazing stock face the same risk horses do, since the oxalates don't change from one animal to the next. Keep cattle, goats, and sheep away from the foliage and any dug-up roots.
Birds Caution
There's little reason to let a pet bird nibble the leaves, and the irritant crystals make it a poor idea. Keep curious beaks away from the plant.
People Caution
No part of this begonia is meant to be eaten, and a bite leaves the mouth burning and stinging. Keep it out of reach of small children who like to taste things.
Most toxic part is underground; keep the plant and any repotting debris (tubers/roots) away from pets and grazing animals
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Most plants sold as polka dot begonia trace back to one well-known cultivar. This is the one worth knowing by name.
Begonia maculata 'Wightii'
A vigorous, free-flowering cane-stem cultivar with long, narrow green leaves dotted in silvery-white spots over deep crimson-red undersides.
How to propagate
Polka dot begonias are easy to multiply, and you don't need any special kit to do it. A cutting taken in the growing season roots on its own with very little fuss.
Stem cuttingsEasy
Spring to summer · Roots in a few weeks (often in water)
Stem and tip cuttings are the easy way to make more of this begonia. Take them in spring or summer while the plant is growing, stand them in water or push them into moist mix, and they root within a few weeks.
Leaf cuttingsModerate
Spring to summer · Several weeks
Begonias will also grow from a single leaf, though it takes more patience. Set a leaf cutting in spring or summer and give it several weeks to form roots and a new plantlet before it's ready to pot on.
Myths
Begonias are barely toxic to pets because only the leaves matter.
Begonia is genuinely toxic to cats, dogs, and horses through calcium oxalate crystals, and the leaves are the mild part. The real danger sits underground in the tubers and roots, which is exactly what a digging pet or a careless repotting can expose.