Croton

Croton: how do you recognise it?

Habit

Upright, branching shrub; as a houseplant usually 60 cm–1.2 m tall and up to 80 cm wide.

Leaves

Thick, leathery and glossy, 10–30 cm long; oval, lobed, ribbon-like or twisted, depending on the cultivar.

Colour

Green with yellow, orange, red, pink or almost black; more light gives warmer, redder tones.

Flowers

Small, inconspicuous white or yellowish flowers in long, thin spikes; rare indoors and not ornamental.

Sap

White milky sap runs from every wound; it is toxic and irritates skin and eyes.

Plants: March–April · Pruning: March–April

Why grow it?

• Few houseplants have such colourful leaves: yellow, orange, red and green on one plant.
• Attractive all year: it keeps its leaves and its colours as long as it gets enough light.
• Every leaf is different: new leaves often open green or yellow and later turn orange and red.
• Brings a warm, tropical feel to the living room or a heated conservatory.
• A large croton makes a striking specimen; young plants fit on a wide windowsill.
• Easy to root from cuttings, so you can replace an old, leggy plant with a young one.

Croton: where does it grow best?

• Plenty of light: right by an east- or west-facing window, or a little way back from a south-facing one. Morning and evening sun bring out the colours; fierce midday sun through glass can scorch the leaves.
• In too dark a spot the new leaves stay green and the plant loses its colours.
• Warmth: 18–24 °C all year, never below 15 °C. No cold draughts and no spot directly above a radiator.
• Humid air: a bright bathroom or kitchen is ideal, or stand the pot on a tray of wet gravel.
• A permanent spot: it dislikes being moved and often drops leaves after a change of place.

Light

Sunny or bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

1.2 m tall, 0.8 m wide

Temperature

Minimum 15 °C

Goes well with

• Rubber plant: Also likes a bright, warm spot and gives a calm green backdrop for the multicoloured leaves.
• Chinese hibiscus: Needs the same bright, warm place and adds flowers in red, orange or yellow.
• Flamingo flower: Glossy leaves and red flowers, and another lover of warmth and humid air.
• Dragon tree: Narrow, upright leaves as a calm contrast next to the broad, colourful croton.

Croton: when and how to plant it?

Plant in March–April.

1. Repot in March or April, every two to three years or when roots grow out of the bottom of the pot.
2. Choose a pot 2–4 cm wider than the old one, with a drainage hole.
3. Use an open houseplant compost, if you like mixed with some perlite or fine bark for better drainage.
4. Set the plant at the same depth as in the old pot, fill in around it with compost and firm lightly.
5. Water with room-temperature water until it runs out of the bottom, and empty the saucer after a quarter of an hour.
6. Wear gloves: when repotting, a leaf or stem easily snaps and releases milky sap.

Care

Watering

Keep the compost lightly moist: water when the top 2 cm feels dry. Use room-temperature water; cold water and waterlogged roots cause leaf drop.

Humidity

Dry air causes brown edges and spider mite. Stand it on a tray of wet gravel, group it with other plants or use a humidifier.

Feeding

From April to September, liquid houseplant feed every two weeks at half the recommended dose. No feed in winter.

Leaves

Wipe the leaves now and then with a damp cloth: dust blocks light and attracts spider mite.

Repotting

Every two or three years in spring, into a pot only slightly larger.

Permanent spot

Leave it where it is happy: any change in light or temperature can make it drop leaves.

Tip: Find the right spot straight away and leave it there: plenty of light, warmth and no draughts. If it still drops a few leaves after you buy it, do not give extra water, but wait patiently for it to shoot again.

Croton: when to prune it?

Pruning months: March–April.

When: Pruning is not needed, but in March or April you can cut back a plant that is too large or leggy. It will then shoot again below the cut.

How:

• Wear gloves and cut with clean, sharp secateurs just above a leaf or bud.
• Shorten stems that are too long or bare by a third to a half; the plant branches again below the cut.
• The sap stops sooner if you wet the wound with lukewarm water or dust it with a little charcoal powder.
• Use the shoot tips you cut off as cuttings.
• Remove the inconspicuous flower spikes so the plant puts its energy into new leaves.

Caution: The milky sap irritates skin and eyes: wash your hands after pruning and do not rub your eyes.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Tip cuttings

In May–July: take shoot tips of 10–15 cm with a few leaves, rinse off the sap in lukewarm water and let the wound dry briefly. Insert them in moist cutting compost under plastic or in a propagator at 22–25 °C. They root within a few weeks.

Air layering

For a tall, bare plant in spring: make a shallow cut in the stem below the leaves, wrap moist sphagnum moss around it and cover with plastic. When roots grow through the moss, cut the top off below them and pot it up.

Croton: how does it get through the winter?

• A true houseplant that stays indoors all year: below 15 °C it drops leaves, and cold can kill it.
• In winter, place it in the brightest spot in the house, close to the window, but do not let the leaves touch the cold glass.
• Water less: let the top layer dry out a little more, and do not feed from October to March.
• Dry air from central heating is the biggest winter problem: do not stand it above a radiator, and raise the humidity.

Diseases and pests

• Leaf drop: Leaves suddenly fall after a move, a draught, cold or cold, wet roots. Give it a permanent, warm, bright spot and water only when the top is dry; it usually recovers and shoots again.
• Green, colourless leaves: The plant is too dark. Move it somewhere brighter, with some morning or evening sun; the new leaves will colour up again.
• Spider mite: Fine yellow speckles on the leaves and webbing underneath, especially in dry air. Rinse the plant under the shower and raise the humidity.
• Mealybug and scale: White fluff or brown bumps along the veins and in the leaf axils, often with sticky leaves. Wipe them off with a cloth and a little soapy water and repeat a week later.
• Brown leaf edges: Air too dry or a dried-out root ball. Water more regularly and raise the humidity.

Through the year

• January: Rest. Brightest spot, little water, no feed. Watch for spider mite.
• February: Rest. Dust the leaves. Keep away from heating.
• March: Repot if needed. Cut back plants that are too large. Start feeding.
• April: Repot or cut back. Feed every two weeks.
• May: Growth. Regular water and feed. Protect from fierce midday sun through glass.
• June: Take tip cuttings or air-layer a bare plant.
• July: Growth. Raise humidity in hot weather. Take cuttings.
• August: Feed. Check for spider mite and mealybug.
• September: Last feed. Move closer to the light as the days shorten.
• October: Water less. Stop feeding.
• November: Rest. Away from draughts and cold windows.
• December: Rest. Little water, keep warm above 15 °C.

Edible and useful

Not edible. All parts of croton are poisonous, especially the white milky sap and the seeds: it belongs to the spurge family. The sap irritates the skin and eyes and can cause a rash in sensitive people; eating any causes a burning feeling in the mouth, vomiting and diarrhoea, in cats and dogs too. The colourful leaves attract children and animals: keep the plant out of their reach and clear up fallen leaves. Wear gloves when pruning and taking cuttings, keep sap out of your eyes and wash your hands afterwards. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• Linnaeus described the plant in 1753 in the genus Croton. It was later moved to the genus Codiaeum, but the old name croton stuck in everyday use.
• It belongs to the spurge family, like the poinsettia, which is why it has the same white milky sap.
• The same leaf turns redder and more orange the more light it gets; in shade it stays greener.