Houseplant · Begoniaceae
Polka Dot Begonia
Begonia maculata
Offer it bright indirect light, careful watering, and humid air, and the polka dot begonia will thank you with spotted, silver-flecked leaves.
Bright indirect
USDA 10–11
2–3 ft · 0.6–0.9 m
Overview
You will understand the polka dot begonia's name the instant it catches your eye. Its long, angel-wing leaves are freckled with silvery-white spots and turn over to reveal a deep crimson-red underside, all held up on tidy, upright, bamboo-like canes. It is one of the cane-stemmed begonias and traces its roots back to the forests of southeast Brazil.
Kept indoors, it stays an easygoing companion, growing to roughly 2 to 3 feet (61 to 91 cm) tall across a few seasons. In the warmer months it may surprise you with drooping clusters of pale pink to white flowers, a lovely little extra on top of the foliage that wins most people over. Its reputation is moderate rather than fussy: forgiving in most things, with just a couple of firm likes.
Those likes really come down to water and air. It dislikes soggy feet and can rot quickly if the soil stays wet, yet it still longs for the high humidity of its native understory. Find that balance, with even moisture and air drifting around the leaves, and you will watch it grow fuller and more radiant each year.
Care
The short version: give it bright indirect light, water only after the top of the soil has dried, and keep the air humid but gently moving. Feed lightly through the growing season and pinch the tips now and then to keep it bushy.
Light
Set it in bright, indirect light by a window that never lets direct sun land on the leaves. It will cope in medium light or partial shade, though the spots dull and the canes stretch. Fierce midday sun can scorch the foliage, so filter it.
Water
Water moderately while it is growing, then let the top of the soil dry before the next drink. This begonia rots easily, so the one rule to hold onto is never to leave it sitting in soggy soil or standing water. Ease off in winter when growth quiets down.
Soil
Reach for a light, well-drained mix rich in organic matter, one that holds a little moisture but lets the rest run through. A slightly acidic pH of 5.5 to 6.5 keeps it happiest. Good drainage is truly the kindest thing you can give it.
Temperature
Keep it warm, and never let the room slip below 55°F (13°C). Cold drafts and chilly windowsills prompt it to drop leaves, so in winter move it away from doors and vents.
Humidity
This plant asks for high humidity, more than most homes naturally offer, so a humidifier or a pebble tray is a real help. The one thing to watch is that humid, still air invites powdery mildew, so pair the moisture with gentle airflow around the leaves.
Feeding
Feed it through the growing season, from spring into summer, using a balanced liquid fertilizer at alternate waterings, roughly every two weeks. Let it rest through autumn and winter and hold off feeding then.
Pruning
Pinch the growing tips to coax out side branches and keep the plant full rather than leggy. Regular pinching also holds its size in check and stops the lower canes from turning bare.
Repotting
Repot every one to two years, or sooner if roots poke through the drainage holes and water rushes straight through. Whenever you do, keep the dug-up roots and tubers away from pets, since those hold the most toxin.
Size & spacing
Indoors it settles at around 2 to 3 feet (61 to 91 cm) tall and spreads 1 to 2 feet (30 to 60 cm) across. Leave it room and airflow on every side to keep mildew from taking hold.
Troubleshooting
Nearly everything that troubles a polka dot begonia comes back to water or air, and the good news is that most of it is easy to catch. Read the leaves and stems early and you can put things right before they spread. Find your plant's signs below, then step in while it can still recover.
Drooping leaves above a mushy, darkened stem base
A soft, darkened stem base sitting in soggy soil points to root and stem rot, and this is the one problem worth acting on quickly. It comes from too much water, and it is the most serious thing that troubles this plant. Even so, all is not lost: tip the plant out, trim away every rotted root and stem, and settle it into fresh, fast-draining mix. Water only once the surface has dried, and it can recover.
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
Pale powdery patches appearing across the foliage
A dusty white coating on the leaves is powdery mildew, and it is very manageable once you spot it. It settles in when humid air sits still and unmoving around the plant. Loosen up the space so a little air can move through, gently pick off the worst-affected leaves, and try to keep water off the foliage. Your begonia still loves humidity, so it is the airflow, not the moisture, that keeps things in balance.
Fix:
- Improve air circulation around the plant
- Remove and discard affected leaves
- Avoid wetting the foliage when watering
Leaves yellowing and falling off
If leaves are turning yellow and dropping, overwatering is usually the gentle culprit, especially when the soil never quite gets to dry out. Cold plays a part too, and a spell below 55°F (13°C) or a persistent draft will make a begonia let go of leaves. The fix is kind and simple: let the top of the soil dry before watering, keep the plant cozy and out of cold air, and make sure the pot can drain freely. It bounces back readily.
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
Fluffy white patches, tacky residue, or delicate webs on the plant
A few sap-sucking pests can visit this begonia, and happily each one leaves a telltale sign. White cottony fluff is mealybugs, little clouds of white flies are whiteflies, fine webbing over speckled leaves means spider mites, and silvery scarring points to thrips. Move the plant apart from its neighbors so nothing spreads, wash off what you can see, then treat with insecticidal soap or horticultural oil. Repeat gently until every last one is gone.
Fix:
- Isolate the affected plant
- Wipe off or wash off visible pests
- Treat with insecticidal soap or horticultural oil and repeat as needed
Bare lower stems stretching upward with foliage left near the top
Take heart, a stretched, leggy begonia is one of the easiest problems to reverse. It happens when the light is a little too dim and the tips have gone unpinched, so nothing has told the plant to branch. Shift it somewhere brighter and start pinching those tips, and if a cane has gone too long you can simply cut it back to a node. Fresh, bushier growth will follow.
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
Do keep this one out of reach of pets and grazing animals. Every part carries calcium oxalate crystals, with the underground tubers and roots holding the most, so a chewed leaf stings the mouth while a dug-up root does more. Nothing on this plant is edible, so keep it away from small children too.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Moderate
A curious cat that nibbles the plant meets a mouthful of calcium oxalate crystals, so watch for drooling, pawing at the mouth, and vomiting. Since the tubers hold the most, tuck any repotting debris safely out of reach.
Dogs Moderate
Dogs respond in much the same gentle way, with drooling and a queasy stomach after tasting a leaf or stem. A dog that digs down and chews the roots takes in a stronger dose.
Horses Moderate
Those same oxalates unsettle horses and other grazing animals, causing mouth irritation and an upset stomach. Bigger or repeated mouthfuls can put a strain on the kidneys.
Rabbits Caution
The very crystals that bother cats and dogs would sting a rabbit's mouth and gut just as much, so it is kindest to treat the whole plant as off limits.
Livestock Caution
Grazing stock share the same risk as horses, because the oxalates behave no differently from one animal to the next. Keep cattle, goats, and sheep clear of the leaves and any unearthed roots.
Birds Caution
There is really no need to let a pet bird sample these leaves, and the irritant crystals make it an unwise treat. Keep inquisitive beaks well away from the plant.
People Caution
No part of this begonia is food, and a bite leaves the mouth burning and stinging. Keep it out of reach of little ones who like to put things in their mouths.
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
Almost every plant sold as polka dot begonia leads back to one well-loved cultivar. This is the one to know by name.
Begonia maculata 'Wightii'
A generous, free-flowering cane-stem cultivar whose long, narrow green leaves wear silvery-white spots above deep crimson-red undersides.
How to propagate
Polka dot begonias are a joy to multiply, and you need no special gear at all. A cutting taken during the growing season roots happily on its own with very little coaxing.
Stem cuttingsEasy
Spring to summer · Roots in a few weeks (often in water)
Making more of this begonia from stem and tip cuttings is wonderfully forgiving. Take a cutting in spring or summer while the plant is actively growing, stand it in a glass of water or tuck it into moist mix, and it will root within a few weeks with barely any effort from you.
Leaf cuttingsModerate
Spring to summer · Several weeks
A single leaf can grow into a whole new begonia too, though it asks for a bit more patience. Set a leaf cutting in spring or summer and give it several weeks to send out roots and a tiny plantlet before you pot it on.
Myths
A begonia poses almost no danger to pets, since its leaves are the only part that counts.
This one is worth gently setting straight. Begonia really is toxic to cats, dogs, and horses through calcium oxalate crystals, and the leaves are only the mild end of it. The greater danger rests underground in the tubers and roots, which is just what a digging pet or an unwary repotting session can bring to the surface.