Aglaonema

Light and exposure

This is the aglaonema’s great asset: it tolerates low light far better than most green plants. A corner of the room away from the window, a hallway, an office without direct sun, all places where it keeps living while another plant would stretch and fade. It needs little to hold on.

That said, low light does not mean total darkness, and the heavily variegated or pink-tinged varieties keep their colours with a little more brightness. Bright but indirect light remains ideal. Avoid direct sun, though, which bleaches and scorches the foliage. In our dark winters, a spot near a window does it good without being essential.

Watering

The aglaonema likes moderate, regular watering, without excess. Let the top third of the substrate dry out between waterings, then water generously, letting the water drain away. Always empty the saucer: a plant left sitting in water ends up with rotten roots.

In winter, when growth slows and light is scarce, space out the waterings clearly. This plant forgives a slight lapse more easily than an excess of water. When in doubt, better to wait an extra day. Water at room temperature suits it better than cold water straight from the tap.

Soil and repotting

A standard, well-draining houseplant potting mix does the job perfectly. To improve aeration, add a handful of perlite or fine bark, which stops the rootball from compacting and holding too much water.

The pot must have a hole in the bottom. Repot only every two to three years, in spring: the aglaonema grows slowly and is even happy a little cramped. Choose a container barely larger so as not to drown the roots in a volume of soil that stays wet too long.

Temperature and humidity

Like all tropicals, the aglaonema likes warmth and hates the cold. Its comfort zone lies between 18 and 27 degrees, that is, the temperature of a lived-in home, all year round. It cannot take dropping below 15 degrees and quickly shows it with spots on the leaves.

Protect it from cold draughts and never leave it against an icy pane in the heart of winter. Keep it away too from the hot, dry air of a radiator, and from the direct blast of an air conditioner, which produces the same drying out in the hot season. A heated, stable room, even poorly lit, remains its favourite environment.

Pruning and upkeep

The aglaonema needs very little pruning. Simply remove yellowed or damaged leaves by cutting them at the base with clean scissors. Wear gloves, as the cut sap is irritating. This cleanup is enough to keep the plant neat and healthy.

Over the years, the stem can go bare at the base and the plant stretch out. You can then cut back the tallest stems to force it to branch and come back bushier. The cut tops will serve as cuttings. Occasionally dusting the leaves with a damp sponge helps the plant capture light better, precious in winter.

Pests and diseases

The aglaonema is little prone to disease, which adds to its reputation as an easy plant. The main risk comes from overwatering: rotting roots, softening stem base, leaves yellowing and dropping. The remedy is simple, space out waterings and empty the saucers.

As for pests, watch for mealybugs, small cottony clusters or brown shells along the stems and under the leaves, and spider mites when the air turns very dry in winter. A cotton bud soaked in 70-degree alcohol deals with isolated mealybugs. Brown spots on the foliage often betray a chill or a draught rather than a disease.

Propagation

Division is the simplest route. When repotting in spring, gently separate the offsets growing around the edge of the clump, each with its own roots, and repot them individually. Wear gloves to handle the cut parts.

Tip cuttings also work on specimens that have stretched out. Cut a stem about ten centimetres long bearing a few leaves, let the wound dry for an hour or two, then place it in water or straight into a light substrate kept moist and warm. Rooting takes a few weeks. A warm, humid atmosphere clearly speeds up recovery.

Toxicity

The aglaonema belongs to the Araceae family, like the dieffenbachia or the philodendron, and its sap contains calcium oxalates in the form of tiny needle-shaped crystals. Chewed or nibbled, a leaf releases these crystals, which immediately irritate the mouth, tongue and throat: a burning sensation, tingling, drooling, sometimes swelling that makes swallowing difficult. Even contact of the sap with skin or eyes can cause redness and itching.

The plant should therefore be kept out of reach of young children and pets, cats and dogs first of all, who sometimes like to nibble the leaves. Serious cases stay rare because the immediate burning cuts off the urge to keep chewing, but the discomfort is real. In case of ingestion, rinse the mouth with water, have the person drink, and contact your national poison centre (in Belgium, the Poison Centre on 070 245 245) or a vet depending on the victim. Wear gloves if you prune or take cuttings, and wash your hands afterwards.

Month-by-month care calendar

Green Hub tips

• It is the plant for dark rooms: where almost everything wastes away for lack of light, the aglaonema holds firm. Perfect for a hallway or a poorly lit office.
• Overwatering is its only real enemy. In winter especially, let the substrate dry out well and always empty the saucer.
• Its sap is toxic and irritating: place it up high, out of reach of children and pets, and wear gloves to prune or take cuttings from it.
• The pink-tinged varieties keep their colours better with a little more light; the green and silver forms get by in shade.
• A cotton bud with 70-degree alcohol removes mealybugs spotted early, before they colonise the plant.