Indoor Begonias: Growing and Care

Botany and description

The indoor begonia belongs to the botanical family Begoniaceae, a vast family comprising over 1,800 species. The genus Begonia takes its name from the French governor Michel Bégon, a passionate botanist in the 17th century, whom the botanist Charles Plumier wished to honour. In French, begonias are often simply called begonias, but some types bear more evocative names such as the bamboo begonia or the rex begonia, famous for its spectacular foliage.

Botanical plates circa 1896: Begonia semperflorens and Begonia rex

In their natural habitat, begonias thrive mainly in tropical and subtropical regions, nestled in humid undergrowth where filtered light and constant humidity provide ideal conditions. This link with shady and humid environments partly explains why they flourish so well indoors. Their great popularity as houseplants is based on several assets: their incredible diversity of shapes and colours, ranging from decorative foliage to vibrant flowering and their ability to adapt to moderate light conditions, perfect for living spaces. Easy to integrate into interior decoration, begonias add a touch of exoticism and refinement, while requiring relatively little maintenance.

Two distinct major families: begonias with colourful foliage and flowering begonias

Among indoor begonias, two major families stand out: begonias cultivated for their spectacular foliage and those prized for their delicate flowers.

Foliage begonias, often associated with the famous Begonia rex, are distinguished by their broad, colourful leaves, often with surprising patterns. Among the most sought-after varieties are the Begonia Rex ‘Escargot’, recognisable by its spiral leaves reminiscent of a snail’s shell, or the Begonia Rex ‘Chayo’, which shines with its vivid and bold hues. Other examples include the Begonia Rex ‘Red Heart’, with its deep and captivating red, the Begonia Rex ‘Dark Mambo’, with its almost mystical appearance in dark tones, and the Begonia Rex ‘Dew Drop’, which brightens interiors with its silvery highlights. The Begonia maculata, with its elongated leaves adorned with white spots, is also an icon among decorative begonias.

Begonia rex ‘Escargot’ and Begonia maculata

On the other hand, flowering begonias charm with their abundant and elegant blooms. Although less extravagant in their foliage, they more than compensate with their delicate and colourful flowers. The Begonia amphioxus offers fine, spotted foliage that harmoniously accompanies its small flowers. The Begonia ‘Pink Pop’, meanwhile, delights with its pink blooms that add a touch of softness. The Begonia eliator, with its rose-like flowers, is another very popular species. Finally, the Begonia semperflorens, also known as the bedding begonia, brings delicate and persistent flowers that illuminate interiors with charming simplicity.

Botanical characteristics of the Begonia genus

The Begonia genus encompasses a great diversity of plants, with varied botanical characteristics, but sharing common traits that make them an easily recognisable and appreciated group.

Plant habit

Begonias display a great variety of habits, ranging from compact and creeping species to more imposing and upright plants. The Begonia maculata, with its slender stems and pendulous wing-shaped leaves, can reach up to 60 cm in height, while the Begonia rex, more compact, forms a dense and low clump.

Begonias of all shapes and habits create a beautiful “jungle” ensemble

Root system

Begonias have three main types of root systems: fibrous, tuberous, and rhizomatous. Rhizomatous begonias, like the Begonia rex ‘Escargot’, develop an underground system consisting of thick rhizomes that allow them to store reserves and produce new shoots. Tuberous begonias, like the Begonia tuberhybrida, have tubers, making them particularly suited to seasonal cycles of dormancy and growth. Finally, fibrous-rooted begonias, like the Begonia semperflorens, have fine and dense roots that easily adapt to various substrates.

Foliage

The foliage is undoubtedly one of the most emblematic traits of the genus. Begonia leaves are often asymmetrical, a unique characteristic in the vegetable kingdom. They display a variety of shapes, colours, and textures. For example, the Begonia maculata offers elongated leaves adorned with white spots, while the Begonia rex ‘Red Kiss’ exhibits broad, velvety leaves marked with intense red patterns. The leaves can be smooth, puckered, or edged with serrations.

Flowering

Begonia flowers, often unisexual (plants bear distinct male and female flowers), vary in size and colour. Flowering begonias, like the Begonia eliator, produce spectacular blooms in shades ranging from white to bright pink, through to red and orange. Each flower is composed of coloured tepals, numbering two to four, which can be single or double.

Flowering of the Begonia maculata

Seeds

Begonias produce extremely fine and light seeds, almost like dust. These tiny seeds, contained in small capsules, require specific conditions to germinate, including indirect light and constant humidity.

Did you know? although they are mainly known as indoor or semi-tropical plants, some begonia species and varieties are sufficiently hardy to be grown outdoors in the garden. This is the case for the Begonia grandis ssp. evansiana, which can tolerate temperatures as low as -10°C when well protected.

Pot planting

When to plant a begonia in a pot?

Spring is the ideal time to plant a begonia in a pot, as temperatures begin to warm and the risk of frost has passed. This coincides with the start of the begonia’s active growth season.

Which substrate to choose?

Begonias prefer a light, well-draining substrate rich in organic matter. A potting mix specially designed for houseplants or a homemade blend of universal compost, turf and perlite is perfect to prevent water stagnation. Adding compost can also enrich the mixture.

Where to place the pot?

Place the pot in a bright spot, but out of direct sunlight, which could scorch the delicate foliage. Indirect light near an east or north-facing window is ideal. If growing a flowering begonia, such as Begonia eliator, ensure it receives enough light to encourage flowering.

Which pot to choose?

A terracotta pot is ideal, as it allows good root aeration and prevents excess moisture, which is common with begonias. The pot size should match the plant: choose one slightly larger than the root ball (about 2–3 cm wider in diameter). A pot that’s too large may retain too much water, risking root rot. Ensure it has drainage holes.

Begonia tuberhybrida

How to plant the begonia?

1. Place a layer of clay pebbles or gravel at the bottom of the pot to improve drainage.
2. Fill the pot halfway with the prepared substrate.
3. Position the begonia’s root ball, ensuring not to bury the collar (the base of the stems).
4. Fill around the root ball with substrate, lightly firm it, then water to moisten the mixture.

Potential repotting

Begonias dislike being root-bound but tolerate staying in their original pot as long as the roots aren’t overcrowded or the substrate too compacted. Repotting every 2–3 years, ideally in spring, is enough to refresh the substrate and give the plant more space. When repotting, choose a slightly larger pot and replace as much substrate as possible without damaging the roots.

Begonia hybrida ‘Gryphon’

Cultivation and care

Watering

Watering should be moderate but regular. Begonias dislike excess water, which can lead to root rot. Allow the surface of the substrate to dry slightly between waterings, then water until water drains from the drainage holes. Use preferably room-temperature, non-calcareous water. In winter, reduce watering, especially for varieties that enter partial dormancy, such as some tuberous begonias.

Fertilisation

During the growth period (spring-summer), apply a liquid fertiliser for flowering or green plants every two to three weeks. Foliage begonias, such as Begonia rex, benefit from a nitrogen-rich fertiliser to support the growth of their decorative foliage. Flowering begonias, like Begonia eliator, will appreciate a balanced or slightly potassium-enriched fertiliser to stimulate flowering. In autumn and winter, stop or reduce fertilisation.

Pruning

Pruning is rarely essential for begonias, but it can be useful to maintain a compact and harmonious plant. Remove yellowed, dry, or damaged leaves to prevent any risk of disease. For flowering begonias, regularly pinch off faded flowers to stimulate the production of new blooms. For some varieties like Begonia maculata, pruning overly long stems also encourages denser branching.

Precautions to take

• Light: Begonias appreciate indirect, soft light. Too much direct light can scorch their leaves, while insufficient light can hinder their growth and limit flowering.
• Humidity: They prefer a slightly humid atmosphere, but avoid misting the leaves directly, as this can cause fungal diseases. If the air is dry, place a tray of water with pebbles under the pot or use a humidifier.
• Temperature: Keep them in a temperate environment between 18 and 24 °C. Begonias dislike cold drafts and sudden temperature changes.

Tip for a long life: rotate the pot regularly to prevent the plant from growing unevenly towards the light. Also, clean dusty leaves with a damp cloth to maximise their ability to absorb light.

Begonia rex ‘Silver Dollar’

Potential parasitic and disease issues

Common Parasites

1. Aphids
   Aphids are small green, black or yellow insects that settle on new shoots or under the leaves. They feed on the sap and weaken the plant, causing deformed or yellowed leaves. To learn more, read our advice sheet Aphids: Identification and Treatments.
   • Solution: treat with a solution of diluted black soap in water.
2. Mealybugs
   Mealybugs can be recognised by their white, cottony clusters on stems or at the base of leaves. They also feed on the sap and weaken the plant. To learn more about mealybugs, read our sheet Mealybugs: Identification and Natural Treatments.
   • Solution: remove them manually using a cotton bud soaked in 70° alcohol.
3. Red spider mites
   These tiny mites thrive mainly in dry, warm environments. They cause yellowed leaves and sometimes a fine web of silk under the foliage. To learn more, read Red Spider Mites: Identification and Treatment.
   • Solution: increase humidity around the plant and treat with a homemade solution based on black soap.
4. Thrips
   These small, elongated insects feed on leaves, leaving silvery spots and discolouration. To learn more, read Thrips: Identification and Natural Treatments.
   • Solution: use blue sticky traps.

Common Diseases

1. Downy mildew
   Downy mildew is a fungal disease that manifests as yellow or brown spots on leaves, often accompanied by a greyish down on the underside. It develops in humid and poorly ventilated conditions.
   • Solution: avoid overwatering and improve air circulation around the plant. Treat with a copper-based fungicidal solution.
2. Powdery mildew
   This disease, also caused by a fungus, forms a white powder on leaves. It usually appears during strong temperature or humidity variations. To learn more, read Powdery Mildew: Prevention and Treatment.
   • Solution: remove affected parts and apply a natural fungicidal treatment, such as a diluted baking soda solution.
3. Root rot
   This occurs due to excess water or poor drainage. The roots turn black and soft, and the plant begins to wither.
   • Solution: if the roots are affected, repot the plant in fresh substrate after removing rotten parts. Be careful not to overwater.
4. Bacteriosis
   Translucent, watery spots may appear on leaves, caused by a bacterial infection favoured by stagnant humidity.
   • Solution: remove affected leaves and avoid watering the foliage. Ensure good ventilation.

General Prevention

• Control watering: water moderately and only when the substrate is dry on the surface.
• Improve ventilation: place begonias in a well-ventilated area, but protected from cold draughts.
• Regular monitoring: inspect leaves, stems and the underside of leaves to detect early signs of parasites or diseases.
• Maintain good hygiene: remove dead leaves and regularly clean the pot and its surroundings to prevent pest proliferation.

Propagating Indoor Begonias

Foliage begonias, such as Begonia rex or Begonia maculata, are usually propagated by cuttings or division, easy and effective methods to reproduce these plants with their unique foliage.

When to propagate?

The best time to propagate foliage begonias is in spring or early summer, when the plant enters its peak growth period and has optimal energy to form new roots.

How to propagate?

1. Leaf propagation by cuttings:
   • Take a healthy, well-developed leaf with its petiole (the stem connecting the leaf to the plant).
   • Cut the leaf into sections if it is large, ensuring each piece contains a main vein.
   • Plant the leaf sections or the petiole in a light mix of compost and sand, vein side down. Keep the substrate slightly moist and place under a cloche or transparent plastic bag to maintain constant humidity.
   • Roots and new seedlings will appear within a few weeks.
2. Stem propagation by cuttings:
   • Cut a healthy stem about 8-10 cm long with 2 to 3 leaves.
   • Remove the lower leaves, keeping only those at the top.
   • Plant the stem in a light substrate, water moderately, and place under a cloche or in a warm, bright spot, but out of direct sunlight.
3. Division of rootstocks (for rhizomatous begonias, such as Begonia rex):
   • Carefully dig up the mother plant and divide the rootstock into several sections, ensuring each piece has at least one bud or shoot.
   • Plant the sections in individual pots with fresh compost.

tuberous begonia

Propagation of flowering indoor begonias

Flowering begonias, such as Begonia eliator or Begonia semperflorens, are mainly propagated by stem cuttings or sowing, depending on the variety.

When to propagate?

Flowering begonias are best propagated in spring or summer, when they are in active growth.

How to propagate?

1. Stem propagation by cuttings:
   • Take a healthy stem 8 to 12 cm long, just below a node, removing the lower leaves to keep only 2 or 3 at the top.
   • Plant the stem in a light, moist substrate (mix of compost and sand or perlite).
   • Place the pot in soft light and under a cloche or plastic bag to maintain high humidity.
   • Roots usually form within 3 to 4 weeks.
2. Sowing (for Begonia semperflorens):
   • Sow the seeds on the surface in a very fine, well-draining mix, as begonia seeds are tiny and should not be covered with substrate.
   • Maintain a temperature between 20 and 22 °C, with constant humidity (place under a transparent plastic lid or in a mini greenhouse).
   • Seeds germinate in 10 to 20 days. Once the seedlings are large enough, transplant them into individual pots.

Tips for successful propagation

• Always use clean and disinfected tools (knives, scissors) to avoid spreading diseases.
• Provide your cuttings or seedlings with soft light and constant humidity, but avoid overwatering, which can cause rot.
• Be patient: some varieties, especially those propagated by sowing or leaf cuttings, take time to develop new roots or seedlings.

How to showcase your begonias?

Decorative-Leaf Begonias: A Graphic and Sophisticated Touch

With their vibrant colours and unique patterns, decorative-leaf begonias like Begonia rex or Begonia maculata blend perfectly with modern, bohemian or contemporary interiors.

• For which interior?
  • Modern or minimalist style: These begonias add contrast and texture, especially in clean spaces dominated by neutral tones (white, grey, beige). The Begonia maculata, with its white spots on a green background, is particularly effective for adding character.
  • Vintage or retro style: Pair them with antique furniture or brass/copper accessories for a cosy atmosphere. The Begonia Rex ‘Escargot’, with its hypnotic spirals, complements this type of décor beautifully.
  • Urban jungle style: In a plant-filled room, a Begonia rex ‘Red Heart’ or ‘Dark Mambo’ becomes a centrepiece thanks to its deep hues and lush appearance.
• In which type of pot?
  • Coloured or textured ceramic pots: Ideal for highlighting the intense tones and leaf patterns. For example, a midnight blue or emerald green ceramic pot pairs beautifully with a Begonia rex ‘Red Kiss’.
  • Natural terracotta pots: Perfect for a bohemian or jungle-inspired interior, as the material enhances the foliage’s complex nuances.
  • Open terrarium: Rhizomatous or compact begonias like Begonia Rex ‘Dew Drop’ are ideal for compositions with mosses and other small plants, creating a mini tropical forest.

Begonia maculata

Flowering Begonias: Delicacy and Romance

Flowering begonias like Begonia eliator or Begonia semperflorens bring a soft, warm ambiance with their abundant and colourful blooms.

• For which interior?
  • Classic or romantic style: The elegant flowers of begonia ‘Pink Pop’ fit perfectly in living rooms or bedrooms decorated with soft textiles, weathered wood furniture and pastel tones.
  • Cottage or chic country style: Begonia semperflorens, with their delicate, evergreen flowers, are perfect for adding a bucolic touch to a kitchen or dining nook.
  • Warm contemporary style: Placed in bright spaces with neutral tones and a few colourful accents, flowering begonias like Begonia amphioxus create a soothing focal point.
• In which type of pot?
  • Pastel ceramic or frosted glass pots: These containers enhance the softness and romance of pink, white or red flowers. For example, a pale pink Begonia eliator will look stunning in a powder-pink ceramic pot.
  • Elegant hanging planters: Trailing or slender-stemmed flowering begonias, like some hybrids, adapt perfectly to macramé or gold metal hangers for an airy decoration.
  • Wicker or rattan cache-pots: Ideal for a rustic or bohemian interior. Begonia semperflorens, for example, find a natural setting that enhances their delicate flowering.

Tips for Incorporating Begonias into Décor

• Group staging: Combine several begonias of different varieties in matching or complementary pots to create a dynamic composition.
• Standalone centrepiece: Place an exceptional foliage begonia like Begonia rex ‘Escargot’ or a flowering begonia like Begonia eliator on a console or coffee table in an elegant pot that draws the eye.
• In a bright corner: Position a Begonia maculata on a stand or shelf near a window to catch indirect light and play with its spotted reflections.

Begonia maculata