Originally from South America, the Tuberous Begonia is a perennial plant appreciated for the bright colors of its large flowers in pots, in suspension, in planters and even in beds.
In summary :
Botanical name : Begonia x tuberhybrida
Common name : Tuberous begonia
Family : Begoniaceae
Height x spread : 60 cm in height and spread approximately. The tubers restart in mid-spring, developing brittle stems. In summer, they take on a drooping habit because of the heavy weight of the flowers.
Blooms : The large single or double blooms of tuberous begonias are beautiful all summer long and cover nearly the entire color palette of the rainbow except for blue.
Foliage: Deciduous, medium green leaves.
Exposure : In the shade or partial shade. Begonias are precious for flowering a shady bed for a very long time. This is largely the reason for their success.
Soil : Humus-rich earth, remaining fresh but well drained.
Hardiness : Frost, 0°C
Tuberous begonia: wintering
After flowering, tuberous begonias go dormant.
In the beds, the tubers are then dug up in the fall using a spade fork to overwinter them in a dry place, protected from frost. The pots are left to overwinter with the pelargoniums.
How to germinate tuberous begonias?
The restart of overwintered begonias is slow. For them to be sufficiently developed before planting in May, they must be taken early and germinated at the end of winter (February) in a bright, warm room.
Start by sorting through the tubers:
- Dispose of those that have dried out and stunted
- If areas of rot have appeared on some, cleanly cut the damaged area with a knife then pass a brush soaked in Bordeaux mixture over the wound or cover it with wood ash.
Then fill a wooden crate or container with a mix of potting soil and sand.
Barely bury the bulbs side by side, with no contact between them. Care must be taken that they are right side up, with the slightly hollowed side facing upwards.
Store in bright light but out of direct sunlight.
Water regularly so that the mixture of soil and sand remains moist, but take care not to wet the tubers to avoid rotting.
Small red eyes appear. Each will form a new leafy shoot.
Keep in bright light to prevent them from fading.
Do not give any fertilizer before the final planting in May, after the end of the frosts.
- Add geranium fertilizer once a month from May to September when growing them in containers.
- Regularly clean up faded flowers to induce new flowers to appear.
- To prevent the stems of large-flowered begonias from breaking, stake them from the start of vegetation.
- Water regularly to keep the soil fresh, but not excessively.
Diseases: powdery mildew, gray rot
Powdery mildew appears especially when the weather is hot, dry and the plant lacks water.
It is quite the opposite for gray rot which develops with excessive watering or when the roots remain submerged.
We act mainly in prevention because once installed, these diseases are difficult to eliminate.
- In spring and summer, treat your plants regularly with horsetail manure or, for more efficiency, with Bordeaux mixture.
- If you grow your Begonias in pots and the weather is very rainy, move them under a roof overhang or on a sheltered window sill.
- Water your plants from the neck, carefully avoiding wetting the foliage.
Tuberous begonia cutting
It takes place in February on begonia bulbs put to germinate. This is a heeled cutting. Follow these steps:
- Cut with a knife a piece that has a few leaves and small roots.
- Repot immediately in a small pot filled with a mixture of potting soil and sand.
- Water lightly
- Stew in full light, under a bell jar or a cut plastic bottle.
- Keep warm, moist potting soil. Ventilate often to avoid rotting.
- Plant in a pot in May.
The Begonia tuberhydrida: a vast family!
Tuberous begonias fall into several groups depending on the type of flowers they bear.
Camellia-flowered and rose-flowered begonias
This is the most important group, also the one that also offers the most beautiful flowers, up to 15 cm in diameter, most often double. In many cultivars, the small female flowers are single and grow on either side of the larger, double male flower. It is necessary to remove these female flowers as soon as they appear to favor the dimensions of the male flower. All colors are possible. This group even features an elegant yellow tuberous begonia that is very bright and trendy!
Their flowers are most often double and are easily recognized by their petals showing a darker border on their edges.
These are tuberous begonias with single flowers grouped in number on the stems. They are grown exactly the same way as the others but need more staking because they tend to sag under the mass of flowers.
They are smaller than the others and their branches are naturally hanging. Like surfinia petunias , they are therefore used to form beautiful suspended flower cascades or planters, especially since the range of colors is vast!