Calathea (peacock plant)

Light and exposure

The calathea lives in the tropical understorey, in the shade of tall trees, so it wants bright but always filtered light, never direct sun. A spot set back from an east or north window, or behind a sheer curtain at a brighter window, suits it well. Direct sun fades and scorches the patterns that make its whole appeal.

In shade that is too deep, on the other hand, the colours fade and the plant weakens. In our winter light, which is weak from November to February, move it a little closer to a bright window while keeping it out of direct sun, which stays rare but low and harsh at this time of year.

Watering

The substrate should stay slightly moist at all times, without ever being waterlogged. Water as soon as the surface starts to dry, roughly twice a week in summer and once a week in winter, adjusting by feel. Neither complete dryness nor excess: the calathea forgives neither.

Above all, the water must be soft. Tap water from the Herve region, hard and chlorinated, browns the leaf edges over time. Use rainwater, demineralised water or tap water left to stand for twenty-four hours, at room temperature. Cold, hard water is the leading cause of damaged leaves on this plant.

Soil and repotting

Use a light substrate that holds a little moisture without becoming soggy: a potting mix for green plants blended with sphagnum peat or coconut fibre, with a handful of perlite for aeration. The pot must have drainage holes despite the need for constant moisture.

Repot in spring every two years, into a pot only slightly larger. The calathea has a fairly fine root system that dislikes being disturbed or drowned in a large volume of soil. A gentle repotting, without breaking up the root ball, is preferable.

Temperature and humidity

The calathea wants constant warmth, between 18 and 24 degrees, and hates variation. Below 15 degrees it suffers, below 12 it can lose its leaves. It tolerates no cold snap or draught, which rules out single-glazed windowsills and entrance halls.

This is where the Belgian climate complicates everything. In winter, central heating dries out the air while the calathea, a plant of the humid understorey, demands high humidity. This is the major constraint: without added moisture, the leaf edges brown and curl up. A humidifier, a tray of moist clay pebbles or grouping it with other plants create the microclimate it needs from November to March.

Pruning and upkeep

The calathea is not pruned for shape. You simply cut off at the base any leaves that are entirely yellowed or dried out, with clean scissors. The brown edges of a still-green leaf can be trimmed back following the natural line of the edge, without hoping to make them disappear entirely.

Dust the foliage with a soft, damp cloth, or give the plant a lukewarm shower from time to time. This cleans the leaves, raises humidity and dislodges spider mites before they settle in.

Pests and diseases

The spider mite (Tetranychus urticae) is the number one pest of the calathea in our dry winters: these tiny mites love the warm, dry air of the heating, speckle the leaves with pale dots and spin fine webs. The best prevention is high humidity; in the event of an attack, shower the plant and raise the humidity level. Keep an eye out for scale insects too.

The brown, dry edges of the leaves are not a disease but the signature of air that is too dry or water that is too hard. Soft leaves and a rotting heart, on the contrary, point to excess water. The calathea demands a precise balance, which is what makes it delicate.

Propagation

The calathea is propagated by dividing the clump, at the time of spring repotting. Turn the plant out of its pot, gently separate the well-rooted clumps by hand, keeping roots and several leaves on each, and repot every division separately in a light, moist substrate.

Keep the young divisions warm, sheltered from draughts, in a humid atmosphere, while they recover, which can take a few weeks. Stem cuttings do not work on this plant, division is the only reliable method.

Toxicity

Non-toxic to cats, dogs and children. It is one of the rare highly decorative plants you can keep without worry in a home with pets.

Month-by-month care calendar

Green Hub tips

• Never water with the region’s hard tap water: the lime and chlorine brown the leaf edges. Rainwater or demineralised water only.
• The dry air of the heating is enemy number one in winter: a humidifier or a tray of moist clay pebbles is almost indispensable.
• Spider mites love warm, dry air: high humidity is your best prevention, not a treatment.
• To propagate, divide the clump at spring repotting; stem cuttings never take on this plant.