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Tuberous begonias: planting and caring for them

Tuberous begonias: planting and caring for them

Tuberous begonias Origin

The genus Begonia within the saffron family includes around 1,400 species worldwide that are native to tropical and subtropical regions of Africa, Asia, South, and Central America.

Tuberous begonias are cultivated forms of various species of this genus, which come from the Andes of Ecuador, Peru, and Bolivia.

The varieties known as Begonia x tuberhybrida are offered as hanging begonias (Begonia pendula) or scented begonias (Begonia odorata).

 Tuberous Begonias Growth

Tuberous begonias grow perennial. They are herbaceous plants that develop an underground rhizome as an outlasting organ. Their stature height ranges between 20 and 40 centimeters (8-15 inches). There are species whose shoots grow flat, creeping, hanging, or towering.

Tuberous begonias: planting and caring for them

Tuberous begonias leaves

The foliage of bulbous begonias is asymmetrical in shape. The leaf blade is heart-shaped at the base and extended to the tip. It has a roughly serrated toothed leaf margin and a raised midrib from which numerous lateral veins spread.

The laterally outgoing nerves branch into smaller leaf veins, each of which ends in a tooth on the edge of the leaf. The leaves are dark green in color, coarse, leathery, and thickened with flesh. There are varieties with reddish-colored foliage.

When do Tuberous begonias blossom?

Tuberous begonias are unisexual. There are both male and female flowers on a plant, which are unfilled in the original forms. Newer breeds have densely filled male flowers. These are non-reproductive, unlike the semi-double female flowers, which have stigmas visible in the center.

The ratio of male and female flowers fluctuates throughout the year depending on the weather. As a result, there are times when the plants have different numbers of double and semi-double flowers.

This is how the flowers of the wild species are structured:

  • similarly shaped bracts
  • male flowers with two to four petals
  • female flowers with two to five petals

The herbaceous ornamental plants prove to be permanent bloomers, whose blooms begin in May and last into October. Some varieties bloom until the first frosts. Tuberous begonias shine in white, yellow, orange, pink, or red.

What are Tuberous begonias used for?

Tuberous begonias are often grown as annual plants. They adorn flower boxes on north-facing balconies. Pre-grown plants start flowering early, making them perfect for the start of the season on the balcony.

Varieties with hanging shoots are used for planting hanging baskets. They decorate interiors, terraces, or house entrances.

Their rhizomes allow perennial cultivation. This makes the plants attractive for arranging flower beds. Due to their site requirements, tuberous begonias are suitable for underplanting shrubs and trees.

They adorn pot arrangements on roof terraces with their splendor of flowers and can be used for indoor greening or cultivated in the conservatory.

Tuberous begonias: planting and caring for them

Which location is suitable for tuberous begonias?

The Begonia hybrids thrive in semi-shade and shady locations. Hours of sunshine in the morning or evening do not bother the plants. They do not tolerate blazing midday sun, as the leaves quickly dry up in the heat of the sun. You should protect the growth site from wind and rain, as shoots and flowers break off or become damaged quickly.

What soil do the tuberous begonias need?

The soil should be rich in nutrients and ensure a loose structure so that the water can drain off well. You can mix some sand under the substrate to improve permeability. Normal potting soil is suitable as a plant substrate.

Propagating tuberous begonias

The simplest method of propagation is propagation by division, which is possible in the spring shortly after fresh sprouting. Dig up the begonia and divide the bulb into about eight sections. Make sure that each piece of the tuber has an eye so that it can sprout.

To make the eyes more visible, you can clean the rhizome with a soft brush. If the root has not developed any shoots, it can be stored in a warm place. When she starts to bud, you can trim the sections accordingly. The parts are placed individually in pots with a permeable substrate and watered.

You should note that:

  • Thoroughly clean knives before cutting
  • Let the tuber pieces dry after dividing
  • Dust interfaces with charcoal
  • Pour away excess water from the saucer

Caring for Tuberous begonias

Tuberous begonias can be started indoors from February to get an early start to the flowering season. The rhizomes germinate when the temperature no longer falls below ten degrees Celsius (50F). They should be soaked in lukewarm water for 24 hours before planting to allow them to swell slightly.

Cover the bottom of a planter with shards of pottery, pebbles, or expanded clay to keep water from accumulating. Fill the pot three-quarters full with substrate. Place the rhizome on the ground so that the root side with the clearly visible indentation is facing up. The tubers should only be half-buried in the substrate. Slightly moisten the substrate.

Place the pot in a place with temperatures between 10 and 15 degrees Celsius(50-59F). A location in the unheated conservatory or in the basement is ideal. The thermometer should not rise any higher, as the fresh shoots develop soft and unstable in locations that are too warm.

As soon as the plant has grown about two to four centimeters (0.7 – 2 inches) high and forms the first leaves, you can place the planter in a brighter and warmer place.

Tuberous begonias: planting and caring for them


The tuber must not stand in a wet substrate. Spray the substrate with water twice a week, making sure that the rhizome does not get any drops of water. A clear cover prevents drying out. This must be removed daily to prevent mold from forming. During rooting, the tuber hardly needs any water. The need increases as soon as the first leaves appear.

The acclimatization phase begins at the end of April. Place the planter outside in a shady spot for several hours every day. The temperatures should be at least 15 degrees Celsius (59F).

In this way, the tuberous begonia is gradually hardened and adapted to the natural weather conditions. In the evening, as a precaution, bring the plant inside so that it is not damaged by late frosts.

Sowing Tuberous begonias

Propagation from seeds requires patience and finesse. They are sprinkled on growing substrate between December and January and slightly moistened. Temperatures between 23 and 26 degrees Celsius (73.4- 78.8) and high humidity are required for the seeds to germinate.

Tuberous begonias are light germs. Therefore, the propagation takes place by means of seeds under plant lamps. So that the heat does not dry out the substrate. glass hoods are put over the planters. Under optimal conditions, the seeds will germinate in two to three weeks. The success rate is not particularly high.

As soon as the first shoots are visible, the temperature is reduced to around 20 degrees Celsius (68F). Humidity must also be reduced. Strong sunlight damages the tender shoots and leaves of the young plants. It can take up to seven weeks before the plants can be transplanted. Only then is cultivation possible at around 15 degrees Celsius (68F).

Tuberous begonias Cuttings

Cut a few leaves from a strong plant and put them in a filled planter. A mixture of potting soil and sand is suitable as a substrate. Keep the substrate moist until roots have formed. The cuttings can then be planted individually or in small groups.

What is the best planting time for Tuberous begonias?

Tuberous begonias are planted out in May when the danger of late frosts has passed. The ice saints serve as a guide for planting out. After this date, you can leave potted plants on the balcony and terrace.

The right planting distance

When planting in groups, pay attention to the growth width of the respective varieties. You need a minimum distance of 40 centimeters (15 inches) to the nearest neighbor.

Tuberous begonias in a pot

Tuberous begonias are ideal for planting in balcony boxes,  flower pots, and hanging baskets. If you plant several tubers in a wide balcony box, you should ensure a distance of 20 centimeters (7.8 inches) between the plants. This way they don’t stand too close together and can develop healthily.

Tuberous begonias: planting and caring for them

Watering tuberous begonias

Tuberous begonias do not like waterlogging as it quickly leads to root rot. Collected water in the coaster should be poured off immediately. Water the plants sparingly. Short dry periods do not cause them any problems. When watering, make sure that the leaves and flowers do not get any water. It is poured directly on the tuber.

Properly cut tuberous begonias

Pruning measures are reduced to a minimum with tuberous begonias. It is more important to regularly clean out withered flowers and leaves. This measure supports the vitality and stimulates the formation of new flowers.

Dead plant parts rot quickly between the densely growing plants, making them more susceptible to disease. If you get the tubers out of the ground for overwintering, cut off the withered parts of the plant to a few centimeters.

Fertilize tuberous begonias properly

To ensure that the flowers shine in all their glory, you can give the plants fertilizer regularly. Liquid fertilizer for balcony plants is ideal. It is fed every 14 days via irrigation water. After flowering, the amount of fertilizer is slowly reduced.

Hibernating Tuberous begonias 

Ornamental plants are not hardy and already die at minus temperatures just below zero degrees (32F). From the end of September, watering and fertilizing will be stopped completely so that the soil can dry.

Get the tubers out of the substrate and clean them with a fine brush. Place the rhizomes in a box filled with sand and place them in a dry and frost-free place with temperatures between five and seven degrees Celsius (41-44F). The tubers should be stored in the dark so that they are not stimulated to germinate in winter.

Tuberous begonias: planting and caring for them

What fungus affects tuberous begonias?

Under unfavorable conditions, tuberous begonias can be affected by fungi. When planting, make sure that the tubers are not too close together. Poorly ventilated crop stands to increase the risk of fungal infestation. Too warm a location can also cause spores to spread.


If the conditions are too wet, there is a risk that the fine roots and rhizomes of tuber begonias will rot. Fungal spores settle in these places, which often survive in the substrate. They penetrate the plant organism with their mycelium and additionally weaken the plant.

As a result, the plant can no longer obtain sufficient water and nutrients, causing the leaves to wither. Infested plants should be removed to prevent the spores from spreading to other plants.

powdery mildew

This fungus is common in gardens and multiplies in dry and warm conditions. It causes a mealy coating on the upper side of the leaves that can easily be wiped off by hand. If the fungus spreads its root network further, the leaves turn brown from the edge to the middle.

Thin out affected plants. If the fungus has spread extensively, the entire plant should be removed.

Tuberous begonias and pests

Weakened plants are more likely to be attacked by pests. You should not over-fertilize the plants and offer them optimal site conditions so that they can develop vigorously and healthily. Extracts from plant extracts can support vitality.


The pests, which are a few millimeters in size, overwinter on the plants in the egg stage and hatch in the spring. The first generation is formed asexually so that the plant is occupied by numerous animals within a short time.

They suck the sap from the veins and leave sticky secretions on the leaves. Spray the plants with a mixture of water and washing-up liquid and wipe off the pests with a cloth.


These pests leave injuries on the leaves, through which air penetrates into the tissue cells. Silvery to white shimmering spots develop in these areas. A heavy pest infestation leads to stunted growth.

You can recognize an infestation by brown droppings that collect on the leaves. Crippled shoots can be a sign. Spray the leaves with lime-free rainwater and make sure the air is not too dry. Neem oil has been proven to be a preventive agent.

vine weevil

The beetle lays its eggs on the substrate. When the larvae hatch, they burrow into the substrate and feed on the roots. Adult insects eat typical patterns in the leaves. They are crepuscular and nocturnal and drop off the plant when threatened.

Nematodes kill the larvae in the soil while special traps are used to catch the beetles.


If your tuberous begonia has been devastated by a storm, you can plant individual leaves in a pot for rooting. In this way, you can also grow beautiful plants in late autumn that will bloom on the window sill for weeks.

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