Begonia Growing Guide: Types, Care and Propagation

Begonias are one of those rare plant families that suits almost every kind of gardener. They’ll fill a shaded border with summer colour, light up a north-facing windowsill with spiralling metallic foliage, and trail luxuriantly from a hanging basket — all depending on which of the 2,000-plus species you choose. The challenge is that “begonia” covers wildly different plants with wildly different needs. What works brilliantly for a sun-loving wax begonia will quickly destroy a rex.

This guide covers everything you need to grow any begonia successfully: how to identify the five main groups and exactly what each one requires, how to water without killing them (the single most common mistake), how to store tuberous types over winter, and how to propagate correctly by group. I’ve also included a month-by-month care calendar — something no other begonia guide seems to provide — because begonias have distinct seasonal demands that are easy to miss without a clear overview.

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The Five Main Begonia Groups

Before you reach for the watering can, the most useful thing you can do is work out which group your begonia belongs to. Each group has genuinely different care requirements, and treating them all the same is the fastest route to a dead plant.

Tuberous Begonias

Tuberous begonias (Begonia × tuberhybrida) produce the most extravagant flowers in the genus — up to 15 cm across, in colours from white and pale lemon to deep crimson and rich orange. They’re native to the Andes, which tells you something immediately: they prefer cool summers, dislike intense midday heat, and go completely dormant over winter.

The classic outdoor use is in shaded or part-shaded containers and hanging baskets, where the large double blooms are impossible to ignore from June to October. UMN Extension’s guide on tuberous begonias identifies overwatering during active flowering as the leading cause of failure, producing bud drop and soft stem rot before most gardeners realise what’s happening [1].

Trailing varieties like ‘Illumination’ and ‘Hanging Basket’ look quite different from upright forms but require identical care — the difference is in the tuber genetics, not the growing method.

Fibrous/Wax Begonias

Wax begonias (Begonia × semperflorens) are the workhorses of summer bedding. They flower continuously from late spring until the first frost, tolerate heat far better than tuberous types, and need almost no attention once established.

One detail most growing guides omit: Clemson’s begonia factsheet notes that bronze-leaved cultivars are significantly more sun-tolerant than green-leaved types, because the anthocyanin pigment responsible for the bronze colour screens excess UV [2]. In practice, green-leaved wax begonias appreciate some afternoon shade in hot summers, while bronze types like ‘Senator Red’ can often manage full sun without scorching.

Dragon Wing begonias (B. × hybrida ‘Dragon Wing’) are often sold alongside wax begonias but are technically cane-type hybrids — larger, more vigorous, and unsuited to the same full-sun treatment.

Rex Begonias

Rex begonias are grown entirely for their foliage — whorled spirals, metallic silver zones, deep burgundy overlays, spotted patterns. They’re rhizomatous plants originating from the forest floors of northeastern India and Southeast Asia, and that origin is the key to understanding their care.

They need warm, humid, low-light conditions. UConn’s rex begonia factsheet specifies humidity above 75% for best foliage development, which is why they thrive in bathrooms or on pebble trays rather than on a dry, bright windowsill [3]. Direct sun bleaches the metallic colouring within days and causes permanent brown patches.

Rex begonias have a normal winter dormancy that catches many growers off guard — in winter they may drop most of their leaves and appear to be dying. This is completely expected. Keep the soil barely moist and wait for new growth to emerge in spring.

Cane/Angel Wing Begonias

Cane begonias grow on segmented, bamboo-like stems that can reach 1.5 m or more indoors, with large often asymmetric leaves and pendulous clusters of flowers in pink, red, or white. Angel wing begonias are the most widely grown subgroup, named for their ear-lobed leaf shape.

These are the most forgiving of the indoor begonia groups. They tolerate lower humidity than rex types, adapt to a range of light conditions, and can go somewhat longer between waterings. One important point for propagation: cane begonias cannot be propagated from leaf cuttings — a fact that catches many growers out when they try the same leaf method that works for rex. They only root reliably from stem cuttings.

Rhizomatous Begonias

Rhizomatous begonias are defined by a thick, fleshy rhizome that creeps across the soil surface. They tend to be compact, low-growing, and more drought-tolerant than other groups — the rhizome stores water and nutrients as a buffer. Iron Cross (B. masoniana), with its unmistakable brown cross marking on corrugated green leaves, is the best-known example. ‘Escargot’ — sometimes listed under rex begonias in garden centres — is technically a rhizomatous type, its silvery-grey spiral unfurling from the centre of each leaf.

One species worth singling out: Begonia grandis is a hardy rhizomatous type that survives outdoors year-round in sheltered UK gardens and to USDA Zone 6 in the US. It dies back completely in winter and re-emerges from underground tubers in late spring — requiring no lifting at all, which makes it unique in the genus.

Indoor vs Outdoor: Matching Type to Setting

Light Requirements by Group

Getting light wrong is the second most common way to kill a begonia. The requirements differ sharply between groups.

Rex begonias are the most commonly over-lit group. I keep mine a metre back from a south-facing window behind a sheer blind — bright enough for healthy growth, but the leaves never receive direct rays. The metallic patterning that makes these plants so desirable fades quickly and permanently if exposed to direct sun.

Watering: The Most Common Begonia Mistake

Overwatering kills more begonias than anything else. The failure mode is always the same: constantly moist soil leads to root rot, which causes soft, collapsing stems. By the time the problem is visible above the compost, the plant is often past saving.

General rule for all types: let the top 2–3 cm of compost dry out before watering, then water thoroughly and allow it to drain completely. Never let any begonia sit in standing water in its saucer.

Rex begonias — bottom watering only

Rex begonias are particularly prone to powdery mildew and botrytis if water sits on their velvety leaves. Bottom watering eliminates this risk: place the pot in a tray of water for 20–30 minutes until the compost surface feels moist, then remove and allow it to drain freely. UConn’s rex care guide also notes that bottom watering encourages deeper root development, which improves overall plant stability [3].

Tuberous begonias — the lift-the-pot test

The American Begonia Society recommends lifting the pot before and after watering to gauge the weight difference — a dry pot is noticeably lighter. This removes all guesswork, particularly in summer when evaporation rates change with temperature. UMN Extension advises reducing watering gradually from late August as the stems start to yellow, easing the plant towards dormancy rather than cutting off water abruptly [1].

Winter watering: reduce to roughly once every two to three weeks for overwintering cane and rhizomatous types. Stored tubers need no water at all once cured and packed.

Feeding and Soil

A free-draining, peat-free multipurpose compost with added perlite — roughly a 3:1 ratio — suits all begonia groups. NC State Extension recommends a slightly acidic pH of 5.5–6.5, which most standard multipurpose composts fall within naturally [4]. If growing in garden soil, incorporate grit or horticultural sand to improve drainage.

Feeding schedule:

• Active growth (April–August): balanced liquid fertiliser (20-20-20 NPK) every two weeks
• Heavy-flowering types (tuberous, wax): switch to a high-potassium feed such as tomato fertiliser from June onwards to support sustained flowering
• Rex and rhizomatous types: half-strength balanced feed monthly — these are foliage plants that don’t benefit from heavy nitrogen
• From September: stop feeding entirely for outdoor types; taper off for indoor types entering dormancy

Overwintering Tuberous Begonias

Tuberous begonias cannot survive frost. Once the first frost blackens the foliage, it’s time to lift and store the tubers. Done correctly, this gives you vigorous tubers that flower reliably for five or more years. OSU Extension’s five-step protocol is the most thorough guide available for this process [5]:

1. Lift after the first frost — wait until foliage has been blackened, then cut stems to 5 cm above the tuber and dig up the clump carefully.
2. Cure for two to three weeks — lay tubers in a single layer on a tray in a dry, frost-free spot at around 15°C. This dries the stems completely and prevents rot spreading into storage.
3. Clean and inspect — remove dried stems, brush off loose soil, and cut away any soft sections with a clean knife. Dust cut surfaces with sulphur powder to prevent fungal rot.
4. Store correctly — place tubers individually in paper bags or cardboard boxes with barely damp vermiculite or wood shavings. Never use plastic bags — trapped moisture causes soft rot within weeks. Store at 4–10°C (40–50°F) in a dark, frost-free location, per UMN Extension [1]. An unheated garage shelf works well.
5. Check monthly — remove any tuber that develops soft spots immediately to prevent spread.

Restarting in spring: pot tubers into fresh compost in late February or early March. The most common beginner error here is planting tuber upside-down. The concave (hollow or indented) side faces upward — that’s where shoots emerge. The convex (rounded) side goes down into the compost. Starting indoors six to eight weeks before the last frost date gives a head start for early summer flowering.

Propagation by Type

Each begonia group roots by a different method. Choosing the wrong approach wastes weeks and usually produces nothing — particularly with cane types, which are often mistakenly treated like rex begonias.

Rex Begonias — Leaf Wedge Cuttings

Rex begonias propagate readily from a single leaf. The wedge method gives reliable results:

1. Take a healthy, mature leaf and cut it into wedge-shaped sections, each containing a section of the central vein.
2. Insert each wedge upright into a tray of 50:50 perlite and multipurpose compost, burying the vein end about 1 cm deep.
3. Cover with a clear propagator lid or loosely draped polythene to maintain high humidity.
4. Keep at 18–21°C in bright indirect light — never direct sun.
5. Plantlets emerge from the base of the veins within four to eight weeks.

An alternative is the slash-vein method: pin a whole leaf flat onto the compost surface and make shallow cuts across each main vein with a sharp blade. BBC Gardeners’ World’s leaf cutting guide demonstrates this technique clearly [8]. The wedge method suits a humidity-controlled propagator; the slash-vein method is easier in an open room. The leaf cutting technique also works well for many rhizomatous types including ‘Escargot’.

Cane/Angel Wing Begonias — Stem Cuttings

Take 10–15 cm stem cuttings just below a node, remove lower leaves, and insert into a free-draining compost mix. Rooting takes three to six weeks at 21°C in a warm, humid spot. Do not attempt leaf cuttings with cane begonias — they lack the cellular capacity to form adventitious buds from leaf tissue and the cutting will simply rot.

Rhizomatous Begonias — Division

Rhizomatous types are best propagated by dividing the rhizome in spring. Use a clean, sharp knife to cut through the rhizome, ensuring each section retains at least one visible growing tip. Pot each division into fresh compost and keep in a warm, humid spot for two to three weeks while establishing. Most divisions recover quickly and will flower in the same season.

Tuberous Begonias — Tuber Division

Large tubers can be divided in spring just as they begin to show shoots. Cut through the tuber so each section has at least one shoot bud, dust cut surfaces with sulphur powder, allow to dry for 24 hours, then plant as normal. Divisions tend to be smaller in the first season than an undivided tuber, but this is the most practical way to increase stock of a favourite variety.

For guidance on potting up any begonia into fresh compost, see our complete guide to repotting houseplants.

Pests, Diseases and Common Problems

Vine Weevil

The most serious pest of container-grown begonias, particularly tuberous types. Adult vine weevils notch the leaf margins (cosmetic but unsightly); the larvae burrow into roots and tubers, often killing the plant before the damage becomes visible above the compost. By the time a plant wilts suddenly in midsummer, the root system is frequently largely destroyed.

The most effective prevention is biological control: apply Steinernema kraussei nematode suspension to container compost in August–September, while soil temperatures remain above 5°C. Chemical drench products containing imidacloprid provide systemic protection for several months and are particularly valuable for high-value tuberous collections.

Mealybugs

Clusters of white waxy wool in leaf axils and stem joints indicate mealybugs. Wipe accessible colonies off with a cotton bud dipped in 70% isopropyl alcohol, then treat the whole plant with insecticidal soap or a neem oil spray, repeating every seven to ten days for three applications. Rex begonias are especially susceptible, particularly when grown in conditions that are too warm and dry.

Powdery Mildew

A white, flour-like coating on leaves and stems is powdery mildew — caused on begonias specifically by the pathogen Erysiphe begoniicola, according to the PNW Pest Management Handbooks [6]. The disease thrives at around 21°C with high humidity and poor air circulation — precisely the conditions many indoor begonias are grown in.

For a detailed breakdown of every disease and environmental issue — including a diagnostic table, stem rot identification, and oedema — see our guide to common begonia problems.

A counterintuitive detail: while humid stagnant air encourages spore germination, very high temperatures actually inhibit it. PNW research found that six consecutive days above 30°C was sufficient to eradicate the pathogen in greenhouse trials. That’s not a practical indoor fix, but it explains why the real solution is improved airflow (a small oscillating fan running intermittently helps significantly) combined with a potassium bicarbonate spray or a proprietary fungicide containing trifloxystrobin. Rex begonias are the most susceptible group; the bottom-watering technique described above removes one of the main infection routes.

Botrytis (Grey Mould)

A fuzzy grey mould on stems and leaves, most common in cool, damp autumn conditions. Remove all affected tissue immediately, improve air circulation, and reduce watering frequency. Botrytis spreads rapidly — it’s one of the main reasons to lift tuberous begonias promptly after the first frost rather than leaving them in the ground as temperatures drop.

Best Begonia Varieties to Grow

There are thousands of begonia cultivars. These are the most reliable performers in each group for UK and US gardeners. For an in-depth look at 20 top-rated cultivars with a side-by-side comparison table, see our guide to the best begonia types and varieties.

Tuberous

• ‘Nonstop’ series — the industry standard for reliability; compact upright habit, masses of 8 cm double flowers in every colour from white to deep red
• ‘Picotee Lace’ — white petals with ruffled red margins; elegant and distinctive in containers
• ‘Illumination’ — trailing habit, ideal for hanging baskets; available in apricot, orange, salmon and rose

Fibrous/Wax

• ‘Senator Red’ — deep red flowers, bronze foliage, reliable in full sun; one of the most dependable bedding begonias
• ‘Whopper Rose’ — giant wax begonia with leaves three times standard size; impressive in large containers
• ‘Dragon Wing Red’ — technically a cane hybrid; very vigorous, excellent in large outdoor pots through summer

Rex

• ‘Escargot’ — the classic; deep green leaf with a silver spiral swirling from the centre, instantly recognisable
• ‘Froggy’ — bright lime-green with a chocolate-brown central zone; particularly striking in low light
• ‘Red Robin’ — dark red metallic leaves with silver spots; one of the most dramatic rex varieties for indoor display

Cane/Angel Wing

• ‘Angel Wing’ — the original; red flowers, silver-spotted leaves, vigorous to 90 cm
• ‘Looking Glass’ — almost entirely silver leaves with a narrow green margin; an ethereal indoor specimen
• ‘Sophie Cecile’ — large pink flowers, vigorous to 1.2 m; the best cane type for a statement indoor plant

Rhizomatous

• B. masoniana (Iron Cross) — the bold brown cross pattern is unique in the plant world; easy in low light
• ‘Stained Glass’ — lime-green leaf with dark veining and a red underside; stunning in shaded spots
• Begonia grandis ‘Alba’ — the hardy species; white flowers, fully winter-hardy in sheltered UK gardens without any lifting

Begonia Care Calendar

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Frequently Asked Questions

Can begonias be grown from seed?

Yes, though the seeds are extraordinarily fine — among the smallest of any ornamental plant. Wax begonias are commonly raised from seed commercially, germinating at 21–24°C pressed gently onto the surface of moist compost without being covered. For home gardeners, plug plants and tubers are far more practical than seed.

Why are my begonia’s leaves turning yellow?

The most common cause is overwatering — waterlogged compost starves roots of oxygen, preventing nutrient uptake even though the soil appears wet. Check the roots for soft rot. Other causes include cold draughts (most begonias suffer below 10°C), insufficient light, or in the case of rex begonias, low humidity causing stress. The gradual yellowing of old lower leaves is also normal and not a sign of a problem.

Do begonias come back every year?

It depends on the type. Tuberous begonias are perennial if the tubers are lifted and stored correctly — they’ll reliably return for five or more years. Rex, cane, and rhizomatous types are evergreen houseplants with no true dormancy. Wax begonias are true annuals outdoors and are not worth attempting to overwinter.

Are begonias toxic to pets?

Yes. All begonias contain calcium oxalate crystals, which cause mouth pain, drooling, and vomiting in cats and dogs. UF/IFAS confirms that tuberous species contain soluble oxalates at higher concentrations, particularly in the tubers [9]. Keep plants out of reach of pets.

Why won’t my tuberous begonia flower?

The most likely causes are insufficient light (tuberous types need two to four hours of bright morning sun outdoors), temperatures consistently above 27°C (which suppresses bud formation — the Andean origin is the reason), or a tuber planted concave side down. Buds forming but dropping before opening usually indicates irregular watering or low humidity around the plant.

Can I keep a wax begonia as a houseplant year-round?

Yes — wax begonias make effective indoor plants on a bright, sunny windowsill and will flower almost year-round with enough light. They’re one of the most beginner-friendly houseplants available. See our guide to the best houseplants for beginners for more options that thrive in similar conditions.

Sources

1. UMN Extension — Tuberous Begonias. URL used inline.
2. Clemson HGIC — Begonia. URL used inline.
3. UConn Extension — Rex Begonia. URL used inline.
4. NC State Extension — Begonia. URL used inline.
5. OSU Extension — Five Steps for Saving Tuberous Begonias. URL used inline.
6. PNW Pest Management Handbooks — Begonia Powdery Mildew. URL used inline.
7. BBC Gardeners’ World — How to Take Begonia Leaf Cuttings. URL used inline.
8. UF/IFAS — Begonias. URL used inline.
9. RHS — Begonias Outdoors. https://www.rhs.org.uk/plants/begonias/outdoors