Cast-iron plant

Cast-iron plant: how do you recognise it?

Habit

Broad clump 50–80 cm tall and wide, which spreads very slowly.

Leaves

Oval to lance-shaped, 30–60 cm long and 8–12 cm wide, glossy dark green, on a sturdy stalk.

Flowers

Small, purple-brown bells right at soil level; indoors they are rarely seen.

Rhizome

Creeping, fleshy rhizome just below the surface, from which the leaves emerge one by one.

Growth

Slow: a few new leaves a year, mainly in spring and summer.

Plants: March–April

Why grow it?

• Grows where almost nothing else will: in a dark corner, a hallway or a cool stairwell.
• Very forgiving: forgetting to water now and then is not a problem.
• Evergreen, clean-lined and timeless, with the same handsome leaves all year round.
• Lives a very long time and can last for decades.
• Copes with cold better than almost any other houseplant.

Cast-iron plant: where does it grow best?

• Partial shade to shade: a spot a few metres from a window, or a north-facing window, is ideal.
• No direct sun: the leaves scorch and get brown or pale patches.
• Normal room temperature is fine; it also tolerates cool rooms of 5–10 °C.
• Not right next to a radiator, or in the draught of an outside door in midwinter.

Light

Bright, out of direct sun or low light

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Sparingly or moderately

Size

0.7 m tall, 0.6 m wide

Temperature

Minimum -5 °C

Goes well with

• Zanzibar gem: Another tough plant for low light and little water.
• Snake plant: Stiff, upright leaves next to the broad, arching leaves.
• Parlour palm: Airy fronds next to the broad leaves, in the same partial shade.
• Boston fern: A fresh, fine texture in a shady spot.

Cast-iron plant: when and how to plant it?

Plant in March–April.

1. Repot in March–April, only when the pot is full of roots, usually every 3–4 years.
2. Choose a sturdy pot with a drainage hole, only a few centimetres wider than the old one.
3. Use compost for foliage plants mixed with some perlite or coarse sand for good drainage.
4. Set the rhizome just below the surface, no deeper than before, and firm lightly.
5. Water after repotting and let the pot drain well; give no feed for the first month.

Care

Watering

Water when the top 2–3 cm are dry, usually every 1–2 weeks. Better too little than too much.

Feeding

From April to September, houseplant feed at half strength once a month. None in winter.

Leaves

Wipe the leaves now and then with a damp cloth; this keeps them glossy and helps them take in light.

Old leaves

Cut yellow or damaged leaves off at soil level.

Repotting

Only when the pot is full, in March–April. It likes being slightly pot-bound.

Tip: One of the toughest houseplants: it tolerates dark corners, dry air and cold hallways. Water sparingly and only repot it once the pot is full.

Cast-iron plant: when to prune it?

When: No real pruning is needed. You can remove old or damaged leaves at any time of year.

How:

• Cut off yellow, brown or torn leaves with sharp scissors close to the soil.
• Trim off just a brown tip if the rest of the leaf is healthy, following the shape of the leaf.
• Remove a few crowded leaves if the clump gets too dense.

Caution: Do not cut off healthy leaves: it only makes a few new ones a year.

Pruning calendar and basic rules

Propagation

Division

In March–April, when repotting, cut the rhizome with a sharp knife into pieces, each with 2–4 leaves and roots. Pot them up separately and keep them a little drier for the first weeks.

Cast-iron plant: how does it get through the winter?

• In winter it likes to be cool, at 10–15 °C, but an ordinary living room is fine too.
• It even tolerates an unheated hallway or stairwell; in a conservatory or outdoors it survives to about −5 °C, but do not expose it to frost on purpose.
• Water less in winter, especially in a cool spot, and give no feed.
• Keep it away from radiators: warm, dry air attracts spider mites.

Diseases and pests

• Root rot: Yellow, limp leaves and wet, musty compost. Water less, let the pot drain and repot in fresh compost if the roots are brown and soft.
• Scorched leaves: Pale or brown patches caused by direct sun. Move it to a darker spot; damaged leaves do not recover.
• Spider mite: Fine yellow speckles and webbing under the leaves, especially in dry, warm air. Rinse the leaves with lukewarm water and keep it cooler.
• Scale insects: Brown scales on stalks and under the leaves, with sticky leaves. Wipe them off with a cloth dipped in soapy water.
• Variegated form turning green: Too much feed or too little light makes the markings fade. Feed less and give it a little more light.

Through the year

• January: Little water, no feed. Dust the leaves.
• March: Repot and divide if the pot is full.
• April: Start feeding, once a month.
• June: Feed. It can now stand outside in the shade.
• August: Feed. A little more water in hot weather.
• September: Last feed. Bring plants that were outside back in.
• November: Less water. Cool is fine, but not close to a radiator.
• December: Rest. Check now and then for spider mite.

Did you know?

• Its English name, cast-iron plant, comes from the fact that it is almost impossible to kill.
• The small, purple-brown flowers appear right at soil level and almost always go unnoticed.
• George Orwell used the aspidistra as a symbol of respectable middle-class life in his novel ‘Keep the Aspidistra Flying’, published in 1936.