Indoor Begonias: Cultivation and Care

Botany and Description

Indoor begonias belong to the botanical family Begoniaceae, a vast family comprising over 1,800 species. The genus Begonia is named after the French governor Michel Bégon, a botany enthusiast in the 17th century, to whom botanist Charles Plumier wished to pay tribute. **In English, begonias are often simply called begonias, but some types bear more evocative names like bamboo begonia or Begonia rex**, 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 moist undergrowth where filtered light and constant humidity offer ideal conditions. This connection with shady and humid environments partly explains why they flourish so well indoors. Their great popularity as indoor plants rests on several assets: **their incredible diversity of forms and colours, ranging from decorative foliage to brilliant flowering** and their ability to adapt to moderate light conditions, perfect for living spaces. Easy to integrate into home decor, begonias bring a touch of exoticism and refinement, while requiring relatively low maintenance.

Two distinct families: begonias with colourful foliage and flowering begonias

Among indoor begonias, **two main families are distinguished: those cultivated for their spectacular foliage and those appreciated for their delicate flowers**.

Foliage begonias, often associated with the famous Begonia rex, are distinguished by their broad and colourful leaves, often with surprising patterns. Among the most prized varieties, we find the Begonia Rex ‘Escargot’, recognizable by its spiralled leaves evoking a snail’s shell, and the Begonia Rex ‘Chayo’, which shines with its bright and bold hues. Other examples include the Begonia Rex ‘Red Heart’, with deep and captivating red, the Begonia Rex ‘Dark Mambo’, with an almost mystical appearance with its dark tones, and the Begonia Rex ‘Dew Drop’, which brightens interiors with its silvery flashes. The Begonia maculata, with its elongated foliage adorned with white spots, is also an icon among decorative begonias.

Begonia rex ‘Escargot’ and Begonia maculata

On the other hand, flowering begonias captivate with their abundant and elegant flowering. Although less extravagant in their foliage, they more than make up for it with their delicate and colourful flowers. The Begonia amphioxus offers fine and spotted foliage that harmoniously accompanies its small flowers. The Begonia ‘Pink Pop’, meanwhile, enchants with its pink blooms that add a touch of softness. The Begonia eliator, with its flowers reminiscent of miniature roses, is another very popular species. Finally, the Begonia semperflorens, also known as bedding begonia, brings delicate and persistent flowers that brighten interiors with charming simplicity.

Botanical Characteristics of the Genus Begonia

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

Plant Habit

Begonias display a wide 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.

A beautiful “jungle” ensemble of begonias of all shapes and habits

Root System

Begonias exhibit 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, possess tubercles, making them particularly suited to seasonal rest and growth cycles. 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. The leaves of begonias 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 and velvety leaves, marked with intense red patterns. The leaves can be smooth, embossed, or edged with dentations.

Flowering

The flowers of begonias, often unisexual (the 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 red and orange. Each flower is composed of two to four coloured tepals, which can be single or double.

Flowering of 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 primarily known as indoor or semi-tropical plants, some species and varieties of begonias are hardy enough to be grown in the ground in the garden. This is the case with Begonia grandis ssp. evansiana, which can tolerate temperatures down to -10 °C when well protected.

Planting in Pots

When to Plant a Potted Begonia?

Spring is the ideal time to plant a potted begonia, as temperatures begin to warm up and the risk of frost has passed. This coincides with the start of the active growth season for begonias.

Which Substrate to Choose?

Begonias appreciate a light, well-draining substrate rich in organic matter. A potting mix specially designed for indoor plants or a homemade mixture of universal potting soil, turf, and perlite is perfect for preventing water stagnation. Adding compost can also enrich the mix.

Where to Place the Pot?

Place the pot in a bright location, but away from direct sunlight, which could burn the delicate foliage. Indirect light near an east or north-facing window is ideal. If you are growing a flowering begonia, such as a Begonia eliator, ensure it receives enough light to promote flowering.

Which Pot to Choose?

A terracotta pot is ideal, as it allows good root breathing and prevents moisture excess, which is common with begonias. The size of the pot should be suited to the size of the plant: choose a pot slightly larger than the root ball (about 2 to 3 cm in diameter larger). A pot that is too large can retain too much water, which may cause 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 with the prepared substrate up to halfway.
3. Place the root ball of the begonia, taking care not to bury the collar (the base of the stems).
4. Complete with substrate around the root ball, press down lightly, then water to moisten the mix.

Possible Repotting

Begonias do not like to be cramped, but they tolerate staying in their original pot as long as the roots do not overflow or the substrate is not too compacted. Repotting every 2 to 3 years, ideally in spring, is sufficient to renew the substrate and provide more space for the plant. When repotting, choose a pot slightly larger in size 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 do not like excess water, which can lead to root rot. Allow the surface of the substrate to dry slightly between waterings, then water until it drains through the drainage holes. Preferably use 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, like Begonia rex, benefit from a nitrogen-rich fertiliser to support the growth of their decorative leaves. Flowering begonias, such as Begonia eliator, will appreciate a balanced fertiliser or one slightly enriched with potassium 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 spent flowers to encourage the production of new blooms. In some varieties like Begonia maculata, pruning overly long stems also helps promote denser branching.

Precautions to Take

• Light: begonias appreciate indirect and soft light. Too much direct light can burn their leaves, while a lack of light can hinder their growth and limit their flowering.
• Humidity: they prefer a slightly humid atmosphere, but avoid directly spraying the leaves, which can cause fungal diseases. If the air is dry, place a water tray with pebbles under the pot or use a humidifier.
• Temperature: keep them in a temperate environment between 18 and 24°C. Begonias do not like cold drafts or sudden changes in temperature.

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

Begonia rex ‘Silver Dollar’

Potential Parasitic Issues and Diseases

Common Parasites

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

Common Diseases

1. Downy Mildew
   Downy mildew is a fungicidal disease that manifests as yellow or brown spots on the leaves, often accompanied by a greyish down on the underside. It develops in humid and poorly ventilated conditions.
   • Solution: avoid excessive watering and improve air circulation around the plant. Treat with a copper-based fungicidal.
2. Powdery Mildew
   This disease, also caused by a fungus, forms a white powder on the leaves. It generally appears in cases of significant temperature or humidity fluctuations. To learn more, read Powdery Mildew: Prevention and Treatment.
   • Solution: remove affected parts and apply a natural fungicidal treatment, such as a solution of diluted baking soda.
3. Root Rot
   This occurs due to excess water or poor drainage. The roots become black and soft, and the plant begins to decline.
   • Solution: if the roots are affected, repot the plant in fresh substrate after removing the rotten parts. Be careful not to overwater.
4. Bacteriosis
   Translucent and watery spots may appear on the leaves, caused by a bacterial infection favored 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 sheltered from cold drafts.
• Regular Monitoring: inspect the leaves, stems, and underside of the 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 the proliferation of pests.

Indoor Begonia Propagation

Foliage begonias, such as Begonia rex or Begonia maculata, are generally propagated by cuttings or division, easy and effective methods for reproducing these plants with unique foliage.

When to propagate?

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

How to propagate?

1. Leaf cuttings:
   • Select a healthy and well-developed leaf with its petiole (the stem that connects the leaf to the plant).
   • If the leaf is large, cut it into sections, ensuring each piece contains a midrib.
   • Plant the leaf pieces or the petiole in a light mix of potting soil and sand, midrib side down. Keep the substrate slightly moist and place everything under a bell jar or a clear plastic bag to maintain constant humidity.
   • Roots and new seedlings will appear in a few weeks.
2. Stem cuttings:
   • Cut a healthy stem about 8-10 cm long with 2 to 3 leaves.
   • Remove the lower leaves to keep only those at the top.
   • Plant the stem in a light substrate, water moderately, and place under a bell jar or in a warm and bright location, but away from direct sunlight.
3. Division of rootstocks (for rhizomatous begonias, like Begonia rex):
   • Gently unearth 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 potting soil.

tuberous begonia

Propagation of indoor flowering begonias

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

When to propagate?

The propagation of flowering begonias is ideally done in spring or summer, when they are in an active growth phase.

How to propagate?

1. Stem 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 and moist substrate (mixture of potting soil and sand or perlite).
   • Place the pot in soft light and under a bell jar 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 and 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 everything under a clear plastic plate or in a mini-greenhouse).
   • The 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 prevent the spread of diseases.
• Provide your cuttings or seedlings with soft light and constant humidity, but avoid overwatering which could cause rot.
• Be patient: some varieties, especially those propagated by sowing or leaf cuttings, take time to develop new roots or seedlings.

How to Enhance the Beauty of Your Begonias?

Decorative-Leaf Begonias: A Graphic and Sophisticated Touch

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

• In which interior?
  • Modern or minimalist style: these begonias bring a touch of 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 in adding character.
  • Vintage or retro style: pair them with antique furniture or brass or copper accessories for a warm ambiance. The Begonia Rex ‘Escargot’, with its hypnotic spirals, matches well with this type of decor.
  • Urban jungle style: in a room filled with plants, a Begonia rex ‘Red Heart’ or ‘Dark Mambo’ becomes a centrepiece thanks to its deep hues and lush habit.
• In what type of pot?
  • Coloured or textured ceramic pots: ideal for highlighting the intense shades and patterns of the leaves. For example, a deep blue or emerald green ceramic pot beautifully complements a Begonia rex ‘Red Kiss’.
  • Natural terracotta pots: perfect for a bohemian or jungle interior, as the material enhances the complex nuances of the foliage.
  • Open terrarium: rhizomatous or compact begonias like the Begonia Rex ‘Dew Drop’ are perfect for arrangements with mosses and other small plants, creating a mini tropical forest.

Begonia maculata

Flowering Begonias: Delicacy and Romance

Flowering begonias, such as Begonia eliator or Begonia semperflorens, create a soft and warm atmosphere with their abundant and colourful flowerings.

• In which interior?
  • Classic or romantic style: the elegant flowers of the begonia ‘Pink Pop’ fit well in living rooms or bedrooms decorated with soft textiles, weathered wood furniture, and pastel shades.
  • Cottage or shabby chic style: the Begonia semperflorens, with their small delicate and evergreen flowers, are perfect for adding a bucolic touch to a kitchen or dining area.
  • Warm contemporary style: placed in bright spaces with neutral tones and a few colourful accents, flowering begonias like the Begonia amphioxus create a soothing focal point.
• In what 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 would look stunning in a powdered pink ceramic pot.
  • Elegant hanging baskets: flowering trailing begonias or those with slender stems, like certain hybrids, fit perfectly in macramé or golden metal hangings for an aerial decoration.
  • Wicker or rattan cache-pots: ideal for a country or bohemian interior. The Begonia semperflorens, for example, find a natural setting that enhances their delicate flowering.

Tips for Incorporating Begonias into Decor

• Group staging: combine several begonias of different varieties in matching or complementary pots to create a dynamic composition.
• Isolated centrepiece: place an exceptional foliage begonia like the Begonia rex ‘Escargot’ or a flowering begonia like the 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 capture indirect light and play with its speckled reflections.

Begonia maculata