Ornamental · Begoniaceae
Wax Begonia
Begonia semperflorens
Give it moist soil, dappled light, and room to breathe, and this begonia rewards you with bloom after bloom from spring to frost.
Partial shade
Every 2–4 days
50–75°F · 10–24°C
USDA 9–11
Overview
The wax begonia flaunts thick, glossy leaves that look freshly polished, in bright green or deep bronze, and it ranks among the easiest flowering plants going. That is exactly why it packs summer beds, borders, and window boxes with color. Small pink, red, or white flowers pour out from spring right up to the first hard frost.
Most gardeners run it as a warm-season annual and love it that way. It is a tender perennial that overwinters only in the mildest zones, so nearly everywhere else it goes in fresh each spring and gets cleared at frost. It keeps a low, tidy shape, rarely past a foot, and looks fantastic massed in a bed or spilling from a pot.
Best of all, it lights up the shady corner where fussier flowers give up. Bronze-leaved kinds soak up more sun, green-leaved kinds want afternoon shade, and both keep blooming with zero deadheading. Keep the soil evenly moist and well drained, and this plant just runs with it.
Care
The short version: dappled light or morning sun with afternoon shade, soil kept evenly moist but never soggy, a monthly feed through the season, and 6 to 12 inches of space between plants so air keeps moving.
Light
Wax begonias thrive in partial shade or morning sun with afternoon shade, and they roll with a wide range besides. The bronze-leaved types soak up full sun the best, while the green-leaved ones scorch in it and beg for shade through the hottest stretch of the day.
Water
Keep the soil evenly moist but well drained, splashing it every 2 to 4 days as the top dries out. Water at the base early in the morning, since foliage left wet under hot sun can scorch and damp leaves invite fungal disease. Those thick waxy leaves have your back, carrying the plant through a brief dry spell.
Soil
Set it in moist, well-drained soil rich in organic matter. A slightly acidic pH of 5.5 to 6.5 hits the mark, and drainage rules everything, since soggy ground is what rots the roots.
Temperature
This plant hits its stride in mild weather, between 50°F and 75°F (10°C to 24°C). It sulks in real heat and drops at the first frost, which is why gardeners run it as an annual.
Humidity
Ordinary outdoor humidity has it covered, so skip chasing a number. Airflow is the real winner, because crowded, humid plantings are exactly where mildew and gray mold pile in.
Feeding
Feed monthly through the growing season with a balanced fertilizer built for flowering bedding plants. That light, steady boost keeps the flowers rolling without pushing soft, floppy growth.
Pruning
Pinch or shear any leggy stems to keep the plant compact and bushy and to fire off fresh branches. The flowers clean themselves up, so you get to skip the deadheading most annuals demand.
Size & spacing
Plants stay compact, hitting 6 to 12 inches (15 to 30 cm) tall and roughly as wide. Space them 6 to 12 inches (15 to 30 cm) apart so air rushes between them and disease loses its grip.
When to plant
Wax begonias burst into growth once the warmth arrives, but frost stops them cold. Kick things off by starting the dust-fine seed indoors in late winter, move the young plants out only after the last frost and once nights hold above 50°F (10°C), and then watch them bloom flat out from early summer until frost finally calls it.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: About 8 to 12 weeks before the last spring frost; do not cover the tiny seed.
- Plant: After all danger of frost has passed and night temperatures stay above 50°F.
- Harvest: Blooms continuously from spring or early summer until frost.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Good news: nearly every wax begonia hiccup traces straight back to too much moisture on the leaves or around the roots. Spot it early and you can turn it around fast with better spacing and smarter watering. Find the match below, then jump on it before it spreads.
A wilting plant with mushy, blackened stems at the soil line
When a plant flops in soaking wet soil, stem or Pythium root rot is the culprit, driven by ground that never drains. The crown and roots go soft, dark, and decayed, and there is no bringing them back. Yank the worst plants, fix the drainage, and pull back on watering before the rot charges through the rest.
Fix:
- Remove severely affected plants
- Improve soil drainage
- Reduce watering frequency
White powdery dust spreading over the leaves and stems
That dusty film is powdery mildew, a fungus that piles in when the air turns humid and stagnant. It wipes off at first but races through crowded plantings, so move fast. Open the plants up to 6 to 12 inches apart, strip the worst leaves, and water at the base in the morning to keep the foliage dry.
Fix:
- Improve spacing and air circulation
- Remove affected foliage
- Water at the base in the morning rather than overhead
Gray fuzz on the flowers as they rot and cave in
Meet botrytis blight, also called gray mold, which storms in during cool, damp, still weather. The tissue turns tan to brown and loads up with gray spores. Cut out the infected parts, throw the planting open for airflow, and keep water off the leaves to shut it down.
Fix:
- Remove and discard infected plant parts
- Increase air circulation
- Avoid overhead watering
Cottony clumps or tiny insects with stippled, distorted growth
Cottony white masses flag mealybugs, while slender crawling specks usually mean thrips, and both attack the stems and leaf undersides. Thrips do the real damage, since they can haul viruses such as INSV and TSWV. Blast off light infestations with water, hit the rest with insecticidal soap, and cut away any heavily infested growth.
Fix:
- Spray off light infestations with water
- Treat with insecticidal soap
- Remove heavily infested plant parts
Toxicity
One firm caution cuts through the fun: keep this plant away from chewing pets. Every part packs calcium oxalate crystals, with the roots holding the most, so a bite leaves the mouth burning, drooling, and sore. Keep it clear of cats, dogs, horses, and grazing animals, and know that no part is safe for people to eat.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Toxic
A cat that chews the leaves or roots grabs a mouthful of sharp oxalate crystals, so watch for heavy drooling, pawing at the mouth, and vomiting. The roots hold the most and deliver the worst burning.
Dogs Toxic
Dogs that dig up and gnaw the roots take the biggest hit. Look for intense mouth burning, heavy salivation, repeated vomiting, and clear trouble swallowing soon after a bite.
Horses Toxic
The same oxalate crystals fire up a horse's mouth and gut, bringing drooling, mouth pain, and colic-like discomfort. A grazing animal that eats a large amount runs the steepest risk.
Rabbits Toxic
The oxalate crystals burn a rabbit's mouth and digestive tract just as they do other animals, so keep the plant well out of reach and never hand any over as forage.
Livestock Toxic
Cattle, goats, and sheep that graze on begonia can take in enough oxalate to spark mouth irritation, drooling, and digestive upset, and a big helping is the real danger.
Birds Caution
Hard data on birds stays thin, but the crystals that burn other animals would sting a curious bird's mouth too, so treat the plant as off limits to play it safe.
People Caution
No part of the wax begonia is meant to be eaten, and a bite leaves the mouth burning. Handling the sap can irritate sensitive skin, so wash up after pruning and keep it away from small children.
Toxicity is oral and gastrointestinal irritation rather than systemic in pets; grazing animals eating large amounts are at greater risk.
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
Wax begonias hit the shelves mostly as named series rather than single cultivars, sorted by leaf color and sun tolerance. These are the standouts you will run into most.
Cocktail Series
A compact, bronze-leaved lineup, with picks like 'Whiskey', 'Vodka', and 'Gin', that powers through full sun better than most wax begonias.
Ambassador Series
Green-leaved and bred to beat the heat, these charge ahead with morning sun and shade through the hot afternoon.
Doublet Series
This series throws full, double, rose-like blooms instead of the plain single flowers most wax begonias put out.
How to propagate
Stem cuttingsEasy
Spring or fall, including from overwintered plants · Roots typically form in about 2 to 4 weeks
Cuttings are the fast, satisfying route, and you can grab them in spring or fall, even from a plant you carried through winter indoors. Snip a healthy stem, or pull a single leaf, and plunge it into a moist, well-drained medium. Roots form in about 2 to 4 weeks, growing into a plant that matches its parent.
SeedModerate
Indoors about 8 to 12 weeks before the last frost · Several weeks from sowing to transplant size
Seed rewards a little patience. Fire it up indoors 8 to 12 weeks before your last frost, scatter the dust-fine seed across the surface without covering it, and slip it gentle bottom heat. It needs several weeks to reach transplant size, so it never heads straight into the garden.
Myths
Wax begonias need full shade and cannot take any sun.
Give them a chance to settle and they tackle a wide range of light. Bronze-leaved cultivars grow and flower beautifully in full sun, while the green-leaved types are the ones angling for afternoon shade.
A quick nibble of begonia will not faze a pet.
Every part packs calcium oxalate crystals, and the roots pack the most. One bite sets the mouth burning and triggers drooling and vomiting in cats, dogs, and horses, so keep curious pets well away from the plant.