Iron cross begonia

Iron cross begonia: how do you recognise it?

Habit

Low, broad clump 30–40 cm tall and up to 50 cm wide, growing from a creeping rhizome.

Leaves

Lopsided heart shape, up to 20 cm long, deeply puckered and bumpy, with fine reddish hairs.

Markings

A dark chocolate-brown cross in the centre of the leaf, along the main veins.

Flower

Small, greenish-white flowers on long stalks; insignificant and rare indoors.

Roots

A fleshy, creeping rhizome with fine roots; it prefers a wide, shallow pot.

Plants: March–April

Why grow it?

• One of the finest foliage begonias: the puckered leaf with its dark cross catches the eye all year.
• Evergreen and compact, ideal on a table or a wide windowsill out of the sun.
• Does well in a bright spot without direct sun, where flowering plants bloom less freely.
• Easy to propagate: new plants grow from a single leaf.
• A fine partner for other foliage plants that like humid air.

Iron cross begonia: where does it grow best?

• Bright light to light shade, without direct sun: strong sun scorches the leaves and fades the markings.
• Warm: 18–24 °C, never below 15 °C, and out of draughts.
• Humid air: a bright bathroom or kitchen is ideal.
• Open, humus-rich compost that stays moist but never soggy.

Light

Bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.4 m tall, 0.5 m wide

Temperature

Minimum 15 °C

Goes well with

• Rex begonia: Even more colour and pattern in the leaves, with the same care.
• Nerve plant: Low, finely veined leaves that also like humid air.
• Calathea: Beautifully marked leaves for a green corner with humid air.
• Maidenhair fern: A fine, airy fern beside the coarse, puckered leaves.

Iron cross begonia: when and how to plant it?

Plant in March–April.

1. Repot in March or April when the rhizome fills the pot, usually every two years.
2. Choose a wide, shallow pot with a drainage hole: the rhizome spreads sideways.
3. Use house plant compost with some perlite or fine bark.
4. Lay the rhizome on or just below the surface, no deeper.
5. Water in moderately and let the excess drain away.

Care

Water

Keep the compost lightly moist: water when the surface feels dry, onto the compost and not over the leaves. A little less in winter.

Humidity

Stand the pot on a tray of wet clay pebbles or group it with other plants. Do not mist the hairy leaves: it causes spots and mould.

Feeding

From April to September, liquid house plant feed at half strength every two to three weeks.

Leaves

Remove old, discoloured leaves with their stalk. Clean off dust with a soft brush.

Repotting

Every two years in spring, into a wide, shallow pot.

Tip: Always water onto the compost and never over the hairy leaves, and provide humidity with a tray of wet clay pebbles rather than by misting. That keeps the foliage handsome and healthy.

Iron cross begonia: when to prune it?

When: It is not really pruned; remove old or damaged leaves as needed.

How:

• Cut off discoloured or damaged leaves with their stalk, close to the rhizome.
• Snip off the insignificant flower stalks when you see them, so the plant puts its energy into the leaves.
• Rejuvenate an overgrown or bare plant in spring by dividing the rhizome.

Pruning calendar and basic rules

Propagation

Leaf cuttings

In spring or summer, insert a healthy leaf with 2–3 cm of stalk in moist cutting compost, or lay a leaf flat on the compost and nick the main veins. Cover with plastic at 20–22 °C; small plantlets appear after 4–8 weeks.

Division

When repotting, cut the rhizome into pieces, each with a few leaves, and pot them up separately.

Iron cross begonia: how does it get through the winter?

• House plant: it cannot take cold and needs at least 15 °C.
• Do not place it against a cold window pane or above a radiator.
• Water a little less in winter and stop feeding; it makes fewer new leaves then.
• Dry air from central heating causes brown leaf edges: raise the humidity.

Diseases and pests

• Powdery mildew: White powder on the leaves, especially with fluctuating temperatures and poor air movement. Cut off affected leaves and give the plant more space.
• Leaf rot and grey mould: Brown, wet patches caused by water on the leaves or overly wet compost. Water onto the compost, remove affected leaves and water less.
• Brown leaf edges: Caused by dry air or dry compost. Raise the humidity and water more regularly.
• Mealybug: White fluffy tufts in the leaf axils and on the leaf stalks. Remove with a cotton bud dipped in methylated spirit.

Through the year

• January: Raise the humidity. Remove old leaves.
• February: Water moderately. Get ready for repotting.
• March: Repot or divide into a wide, shallow pot.
• April: Start feeding again. Take leaf cuttings.
• May: Water regularly, onto the compost.
• June: Feed every two to three weeks. Keep out of the sun.
• July: Water and feed. Raise the humidity in hot weather.
• August: Take leaf cuttings. Check for mildew.
• September: Last feed.
• October: Water less. Stop feeding.
• November: Keep it warm, not against a cold window.
• December: Water moderately. Raise the humidity.

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?

• It is named after Maurice Mason, an English plant collector who brought it to England in the 1950s.
• A single leaf can produce several new plants: wherever you nick a vein, roots and a shoot can form.
• The genus Begonia is named after Michel Bégon, a 17th-century French administrator who supported botany.