Croton

The croton comes from the tropical islands and coasts of the western Pacific and southern Asia, where it grows as a shrub in bright humid conditions with no cool season at all. It is grown for its leaves, which in a well lit plant carry green, yellow, orange, red and purple at once, often on the same leaf. It has a reputation for being difficult, and the reputation is earned, but the difficulty is narrow: it hates change, it wants more light than most houseplants, and it will not tolerate dry cold air. Give it a warm bright corner and stop moving it, and it is not hard at all.

Light

Several hours of bright light, including some gentle direct sun in the morning or late afternoon. This is not a preference; the colour is made by light. A croton in a dim room does not die, it fades: every new leaf comes out plain green, and over a year or two a spectacular plant becomes an ordinary shrub. The leaves that have already coloured keep their colour, so the change creeps up on you.

Harsh midday sun through glass is still too much and bleaches the leaves, so bright with the fiercest hours filtered is the target.

Water and humidity

Keep the compost lightly moist through the growing season, watering when the top 2 to 3 cm is dry, which is roughly every five days, and a little drier in winter at about every ten. It does not want to stand wet, and it will drop leaves if it dries out completely.

Humidity matters nearly as much as light. It comes from coastal tropics and a heated dry room gives it crisp edges and spider mites in short order. Group it with other plants, stand it on a tray of wet pebbles, and keep it away from radiators and draughty doorways.

Why it drops its leaves

Almost every croton loses leaves at some point, and almost always for the same reason, which is change. The journey home from the shop is the classic trigger, and so is a draught, a cold night, a move to another room, or a repot. The plant is not dying. Put it somewhere warm, bright and still, keep the compost lightly moist, resist the urge to feed it or repot it, and leave it alone. Most plants push out new leaves within two months.

The practical lesson is to choose its position before you bring it home, and then not to move it.

Feeding and repotting

Feed at half strength monthly from spring to early autumn and stop in winter. Repot in spring, one size up, only when roots have filled the pot, and expect a round of leaf drop afterwards.

Pruning and propagation

Cut the stems back by up to a third in spring if the plant has gone tall and bare at the bottom. New shoots break from below each cut, and the plant fills out again over a season. Wear gloves, because the milky sap irritates skin and stains.

Cuttings root reasonably well with warmth. Take a stem with three or four leaves in late spring, blot the cut until the sap stops, and push it into damp compost under a clear cover or a plastic bag, somewhere warm and bright. Bottom heat makes a real difference. Air layering is the better method for a tall bare stem, and gives a full sized plant.

Ailments

Leaf drop is change. Green new leaves are too little light. Fine webbing is spider mites and dry air. Crisp brown edges have the same cause. A long bare stem is a light problem with a pruning solution. The ledger below has the rest.