Peace lily

Light and exposure

The peace lily prefers bright but indirect light, like the understorey it comes from. A spot one metre from an east- or north-facing window suits it very well. The direct summer sun scorches and bleaches the foliage, while too little light reduces or stops flowering, without killing the plant for all that.

If your peace lily makes fine leaves but no longer flowers, it is often a lack of light: move it closer to a window, without direct sun. Under our grey winters, a brighter spot from November to February helps it keep a few flowers.

Watering

It is one of the few houseplants that likes a substrate always slightly moist, but never soaked. Water as soon as the surface starts to dry, on average once or twice a week in summer and once a week in winter. The plant needs more water than average, but equally hates stagnant water in the saucer.

Its great advantage is that it warns you. When its leaves soften and droop all at once, it is thirsty: a good watering straightens it up within a few hours, with no aftermath if the lapse did not last. Just avoid letting it wilt repeatedly, which eventually damages the foliage. Tap water is fine, but if the tips turn brown, let the water stand overnight or collect rainwater.

Soil and repotting

A rich, light potting soil for green plants suits it, lightened with a handful of perlite to keep it from compacting and becoming suffocating. The pot must have drainage holes: the peace lily likes moisture, not water stagnating around the roots.

Repot in spring every one to two years, as the plant grows fast and fills its pot with roots. Choose a container only slightly larger. A rootbound clump dries out very fast and makes the plant droop in no time; this is often the sign that it is time to repot.

Temperature and humidity

The ideal range is 18 to 26 degrees. Below 12 degrees the plant suffers, and the cold blackens its foliage. It tolerates no frost and hates cold draughts near doors and windows.

The real Belgian problem is the dry air of central heating from November to March. This plant of the humid understorey reacts quickly: the tip and edge of the leaves turn brown and dry out. Mist the foliage, place the pot on a bed of moist clay pebbles, or run a humidifier. This is the main constraint of growing it in our heated interiors.

Pruning and upkeep

The peace lily is not pruned for shaping. Cut at the base, with a clean tool, the faded flowers whose spathe has turned green then brown, as well as the yellowed or damaged leaves. This keeps the plant tidy and encourages it to produce new flowers.

Regularly wipe the glossy foliage with a damp cloth to remove dust and let the plant capture the light. Also trim the browned tips if they bother you, following the shape of the leaf, without cutting into the green, healthy part.

Pests and diseases

The main enemy is an excess of stagnant water, which rots the roots: leaves yellowing en masse, a soft base, soil that smells stale. Take the rootball out, cut away the brown, soft roots, and repot in fresh substrate. Conversely, brown, dry tips betray air that is too dry rather than a disease.

As for pests, watch for mealybugs and red spider mites, favoured by the dry air of winter. Clean with a cotton pad soaked in diluted methylated spirits and raise the room’s humidity. Regularly dusted foliage and good humidity clearly limit these attacks.

Propagation

Clump division is the only simple and reliable method, and it succeeds almost every time. At the spring repotting, take the plant out, spot the natural offsets of the clump, and separate them by hand or with a clean knife, making sure each piece keeps leaves and a good bunch of roots. Repot each offset in a suitable pot.

The peace lily cannot be propagated by leaf or stem like a vine: without division, you get no new plant. The best time to divide coincides with repotting, when the plant enters active growth and recovers quickly from the operation.

Toxicity

The whole plant contains calcium oxalate crystals. Chewed, a leaf strongly irritates the mouth, tongue and throat, and makes you salivate. Keep the peace lily out of reach of cats, dogs and young children.

Month-by-month care calendar

Green Hub tips

• The peace lily warns you when it is thirsty: its leaves droop all at once and straighten up within a few hours after a watering.
• Fine leaves but no more flowers? It is almost always a lack of light. Move it closer to a window, without direct sun.
• Against the brown tips of the heated winter, place the pot on moist clay pebbles and mist: it is a plant of the humid understorey.
• To propagate, divide the clump at the spring repotting. The peace lily cannot be propagated by stem like a vine.