Tuberous begonias: planting and caring for

Tuberous begonias: planting and caring for


The genus Begonia within the slate family includes around 1,400 species worldwide that are native to tropical and subtropical regions of Africa, Asia, and 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 begonia (Begonia pendula) or scented begonia (Begonia odorata).

also read

  • Plant tuberous begonias in good time
  • Can tuberous begonias overwinter in pots or boxes?
  • Prefer tuberous begonias and thus extend the flowering time


Tuberous begonias grow for several years. They are herbaceous plants that develop an underground rhizome as a survival organ. Their height is between 20 and 40 centimeters. There are species whose shoots grow flat, creeping, or towering.


The foliage of the tuberous begonias is asymmetrically shaped. The leaf blade is heart-shaped at the base and drawn out towards the tip. It has a roughly serrated to serrated leaf margin and a raised central rib, from which numerous side veins spread. The nerves going off the side branch out into smaller leaf veins, each of which ends in a tooth on the leaf edge. The leaves are dark green in color, thick leathery and fleshy. There are varieties with reddish colored leaves.


Tuberous begonias are unisexual. There are both male and female flowers on a plant, which are unfilled in the original forms. Newer cultivars have densely double male flowers. In contrast to the semi-double female flowers, where scars are visible in the center, these are not capable of reproduction. The ratio of male and female flowers fluctuates over the course of the year depending on the weather. As a result, there are times when the plants have different numbers of double and half-double flowers.

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

  • identically designed bracts
  • male flowers with two to four petals
  • female flowers with two to five petals


The herbaceous ornamental plants turn out to be permanent bloomers, the blooming splendor of which begins in May and lasts until October. Some varieties bloom until the first frosts. Tuberous begonias shine in white, yellow and orange, pink or red.


Tuberous begonias are often grown as annual plants. They adorn flower boxes on balconies facing north. Plants that are moved forward start flower development early, so they are perfect for the start of the season on the balcony. Varieties with hanging shoots are used to plant hanging baskets. They decorate interiors, terraces or house entrances.

Their rhizomes enable cultivation for several years. This makes the plants attractive for the design of flower beds. Due to their location requirements, tuberous begonias are suitable for underplanting shrubs and trees. With their splendor of flowers, they adorn pot arrangements on roof terraces and can be used for interior greening or cultivated in the winter garden.

Which location is suitable?

The Begonia hybrids thrive in partial shade and in shady locations. The plants don't mind hours of sunshine in the morning or evening. They cannot stand the blazing midday sun, as the leaves quickly dry up in the heat of the sun. You should protect the place of growth from wind and rain, as shoots and flowers break off or are quickly damaged.

What soil does the plant need?

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

Propagate tuberous begonias

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

For better visibility of the eyes, you can clean the rhizome with a soft brush. If the root has not developed any shoot eyes, it can be stored warm. When it starts to bud, you can trim the pieces accordingly. The parts are placed individually in pots with a permeable substrate and watered.

You should consider:

  • Thoroughly clean the knife before cutting
  • Let the pieces of tubers dry after dividing
  • Dust the interfaces with charcoal
  • Pour away excess water from the coaster


Tuberous begonias can be grown indoors from February so that they start the flowering season early. The rhizomes germinate when the temperatures no longer drop below ten degrees Celsius. They should be stored in lukewarm water for 24 hours before planting so that they swell slightly.

Cover the bottom of a planter with potsherds, pebbles or expanded clay (€ 17.50 on Amazon *) so that the water does not build up. 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 halfway in the substrate. Slightly moisten the substrate.

Put the pot in a place with temperatures between ten and 15 degrees Celsius. A location in the unheated winter garden or in the basement is ideal. The thermometer should not rise any higher, as the fresh shoots develop softly and unstably in places that are too warm. As soon as the plant has grown about two to four centimeters high and the first leaves are forming, you can move the planter to a lighter and warmer place.

Care and further culture

The tuber must not stand in wet substrate. Spray the substrate with water twice a week and make sure that the rhizome does not get drops of water. A transparent cover prevents it from drying out. This must be removed every day so that mold does not develop. The tuber hardly needs any water during the rooting process. The need increases as soon as the first leaves can be seen.

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

Continue reading


Propagation via seeds requires patience and a sure instinct. They are sprinkled on growing substrate (9.05 € at Amazon *) between December and January and slightly moistened. In order for the seeds to germinate, temperatures between 23 and 26 degrees Celsius and high humidity are required. 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 germinate after 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. The humidity must also be reduced. Strong sunlight damages the tender shoots and leaves of the young plants. It takes up to seven weeks before the plants can be pricked out. Only then is cultivation possible at around 15 degrees Celsius.


Cut off some 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 time to plant?

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

The correct planting distance

When planting in groups, pay attention to the width of the respective varieties. Some tuberous begonias grow expansively. You need a minimum distance of 40 centimeters to the nearest neighbor.

Tuberous begonias in a pot

Tuberous begonias are ideal for planting balcony boxes, (€ 106.25 at Amazon *) flower pots and hanging baskets. If you put several tubers in a wide window box, you should make sure there is a distance of 20 centimeters between the plants. So they are not too close and can develop healthily.

Water the tuberous begonias

Tuberous begonias do not like waterlogging, as it quickly leads to root rot. Any water collected 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. The tuber is poured directly.

Cut the tuberous begonias correctly

Cutting measures are reduced to a minimum with tuberous begonias. Regular cleaning of dead flowers and leaves is more important. This measure supports vitality and stimulates new flower formation. Dead plant parts rot quickly between the densely growing plants, making them more susceptible to disease. When you take the tubers out of the ground for wintering, cut off the withered parts of the plant to within a few centimeters.

Fertilize tuberous begonias properly

So that the flowers shine in full splendor, you can give the plants regular fertilizer. A liquid fertilizer for balcony plants is ideal. It is added every 14 days via the irrigation water. After the flowering period, the fertilizer application is slowly reduced.


The ornamental plants are not hardy and die at temperatures below zero. From the end of September watering and fertilizing will be completely stopped so that the earth can dry out. 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 it in a dry and frost-free place with temperatures between five and seven degrees Celsius. The tubers should be stored in a dark place so that they are not stimulated to germinate in winter.

Continue reading

Fungal attack

Under unfavorable conditions, tuberous begonias can be attacked by fungi. When planting, make sure that the tubers are not too close together. Poorly ventilated crops increase the risk of fungal attack. A location that is too warm can also cause spores to spread.


If the conditions are too wet, there is a risk that the fine roots and rhizomes of the tuberous begonias will rot. Fungal spores settle in these places and often survive in the substrate. With their mycelium, they penetrate the plant organism and also weaken the plant. As a result, the plant can no longer supply itself with sufficient water and nutrients, so that the leaves wither. Infested plants should be removed to prevent the spores from spreading to other plants.

Powdery mildew

This fungus is common in gardens and reproduces in dry and warm conditions. It creates a floury coating on the top of the leaves that can be easily wiped off by hand. If the fungus spreads its root network, the leaves turn brown from the edge to the center. Light up infested plants. If the fungus has spread strongly, the entire plant should be removed.


Weakened plants are preferentially 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, hibernate on the plants in the ice stage and hatch in spring. The first generation is asexually formed, 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 that allow air to penetrate the tissue cells. Silvery to white shimmering spots develop in these areas. Heavy pest infestation leads to stunted growth. You can recognize an infestation by brown globules of excrement that collect on the leaves. Crippled shoots can be a sign. Spray the leaves with lime-free rainwater and make sure that the air is not too dry. Neem oil has been shown to be a preventative.

Vine weevil

The beetle lays its eggs on the substrate. When the larvae hatch, they dig into the substrate and feed on the roots. Adult insects eat typical patterns in the leaves. They are crepuscular and nocturnal and let themselves fall from the plant in case of danger. Nematodes kill the larvae in the soil, while special traps are used to catch the beetles.


If your tuberous begonia was devastated by a storm, you can plant individual leaves in a pot for rooting. You can also use this method to grow beautiful plants in late autumn that will bloom on the windowsill for weeks.


  • Crispa marginata : flowers from June to November. Flowers bright yellow and pure white with red edges.
  • Marmorata : large-flowered variety. Flowers marbled in red and white. Height between 15 and 30 centimeters.
  • Cascade : Constant bloomer with hanging shoots. Flowers white. Grows 6 to 12 inches tall.