Hardy begonia

Hardy begonia: how do you recognise it?

Habit

Loose, branching perennial 40–60 cm tall, with reddish, slightly fleshy stems.

Leaf

Large, lopsided heart shape, olive green above, veined red beneath.

Flower

Hanging sprays of pink or white flowers 2–3 cm across, with separate male and female flowers.

Flowering

From August to October.

Bulbils

In autumn, small bulbils grow in the leaf axils, drop off and form new plants.

Flowering: August–October · Plants: April–May · Pruning: November

Why grow it?

• A real begonia that stays outside and comes back every year.
• Flowers in late summer and autumn, when the shade border is often quiet.
• Handsome leaves with red veins beneath, especially when lit from behind.
• Suits part shade to shade, under trees and shrubs.
• Spreads by itself through bulbils, without becoming invasive.

Hardy begonia: where does it grow best?

• Part shade to shade; no harsh midday sun.
• Loose, humus-rich soil: loam or woodland soil with plenty of leaf mould.
• Moist but well drained; no wet feet in winter.
• A sheltered spot under trees or against a north-facing wall.
• Plant 30–40 cm apart, in groups of three or more.

Light

Partial shade and shade

Soil type

Loam or peat

Acidity

Acid or neutral

Moisture

Normal

Size

0.6 m tall, 0.4 m wide

Hardiness

Hardy (to -15 °C)

Goes well with

• Hosta: Large leaves in the same part shade, appearing earlier to fill the gap in spring.
• Ferns: Fine texture beside the large begonia leaves.
• Japanese anemone: Flowers at the same time in late summer, in pink and white.
• Toad lily: Another late flowerer for the shade border.
• Hellebore: Fills the spot in spring, while the begonia is still asleep.

Hardy begonia: when and how to plant it?

Plant in April–May.

1. Plant tubers or potted plants in April–May.
2. Set the tubers 3–5 cm deep, hollow side up.
3. Mix leaf mould or compost into the soil.
4. Mark the spot: it does not appear until June and is easily forgotten.
5. Water after planting and keep the soil lightly moist.

Care

Water

Keep the soil moist in summer; do not let it dry out.

Feeding

Some compost or leaf mould in spring is enough.

Mulching

A layer of leaf mould in autumn protects the tubers and feeds the soil.

Patience

It emerges late: do not dig in that corner in spring.

Slugs

Protect the young shoots from slugs in June.

Tip: Plant early spring flowers such as snowdrops or wood anemones among them: they fill the empty spot until the begonia appears in June.

Hardy begonia: when to prune it?

Pruning months: November.

When: After the first night frost, in November.

How:

• Cut the dead, limp stems off just above the ground.
• Let the bulbils ripen and drop first, or collect them to plant elsewhere.
• No other pruning is needed.

Caution: Leave the spot alone until June: the tubers are still in the ground, even if you see nothing.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Bulbils

In October, collect the bulbils from the leaf axils and set them 2 cm deep in a pot or straight in the ground.

Division

Older tubers can be carefully lifted and replanted in spring.

Hardy begonia: how does it get through the winter?

Hardy to −15 °C: protect young plants.

• Hardy to about −15 °C in well-drained soil.
• The plant dies back completely above ground in autumn.
• A layer of leaf mould or mulch protects the tubers.
• In wet, cold soil the tubers may rot.

Diseases and pests

• Does not come back: Often just late: wait until the end of June. Or rot caused by wet winter soil.
• Slug damage: On the young shoots in June. Protect them with a slug collar or ferric phosphate.
• Scorched leaves: Too much sun. Move it to a shadier spot.

Through the year

• April: Plant tubers.
• May: Planting. Mark the spot.
• June: The first shoots appear. Protect against slugs.
• July: Water in dry spells.
• August: Start of flowering.
• September: Full flower. Bulbils form.
• October: Last flowers. Collect bulbils.
• November: Cut off dead stems. Mulch.

Edible and useful

Not edible. All begonias are poisonous, especially the tubers and roots: they contain oxalates which, when chewed, cause a burning feeling and irritation of the mouth and throat, with drooling and vomiting, in children as well as in cats and dogs; grazing animals and rabbits can fall ill from them too. Tuberous begonias overwinter dry in a box or pot: store the tubers out of reach of children and pets, and not with the potatoes. Indoor begonias often stand on the windowsill, at a child’s height and within a cat’s reach: put them higher up or in another room. The flowers of tuberous begonia sometimes appear on lists of edible flowers, but because of the oxalates they are best not eaten, especially if you have kidney stones. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• Begonias are named after Michel Bégon, a 17th-century French administrator who supported botany.
• Begonias carry separate male and female flowers on the same plant; you can tell the female ones by the winged ovary behind the flower.