ZZ plant

Light and exposure

The ZZ plant tolerates a wide range of light, from bright filtered light to a distinctly dark corner. In good filtered light it grows faster and forms compact, well-filled stems. In shade it slows down sharply but survives where almost everything else gives up, which explains its reputation as an office and corridor plant.

Avoid direct summer sun, which yellows and scorches the leaflets. Its very good shade tolerance makes it one of the few plants that gets through the low light of the dark season without harm, without needing to be right up against a window.

Watering

This is where everything is decided. The ZZ plant’s rhizome is a water reserve: it fears excess far more than drought. Let the substrate dry out completely before watering again, meaning a watering every two to three weeks in summer, and about one a month in the cold season.

At rest and in little light, the plant consumes almost nothing. The classic mistake is to water it at the same pace as in summer and rot the rhizome. Stems that yellow and soften at the base betray this excess water. A ZZ plant forgotten for an extra month risks nothing, whereas an overwatered plant is quickly lost. When in doubt, do not water.

Soil and repotting

It needs a free-draining substrate that does not trap water around the rhizome. Mix potting soil for green plants with a good share of perlite and a little coarse sand, or use a lightened cactus mix. The pot must be pierced, without exception.

The ZZ plant grows slowly and likes to be cramped. Repot only every three or four years, in spring, when the rhizome makes the pot bulge or crack. A terracotta container, which lets the root ball breathe, reduces the risk of rot compared with a watertight plastic one.

Temperature and humidity

The comfortable range is between 18 and 26 degrees. Below 12 degrees, growth stops and marked cold damages the foliage. The ZZ plant tolerates no frost and dislikes cold draughts.

Its strength is to tolerate very well the dry air of heating throughout the heating season, without misting. It lives at room temperature all year. The only winter pitfall is not the cold but the watering: at rest, the plant needs barely any water, and it is the overflow, not the drought, that puts it at risk.

Pruning and upkeep

The ZZ plant is not pruned into shape, it grows on its own in even upright stems. Just cut off at the base, with a clean tool, whole stems that yellow, dry out or collapse. A damaged stem cannot be repaired.

Wipe the leaflets regularly with a damp cloth. Their glossy surface gathers dust, which dulls their fine shine and limits the light captured. No need for a leaf-shine product: a simple damp cloth is enough to restore their natural gloss.

Pests and diseases

The ZZ plant is very little prone to disease. The only real risk is rot of the rhizome and roots, caused by excess water: the stems yellow and soften at the base, the rhizome smells bad. You must take the plant out, cut back cleanly everything that is soft, let the healthy parts dry and repot in a dry, free-draining substrate.

As for pests, you sometimes meet mealybugs and, when the air is very dry, red spider mites. They remain rare on this thick, tough foliage. Cotton soaked in diluted methylated spirit is enough to treat mealybug outbreaks spotted early.

Propagation

Dividing the rhizome is the fastest method. At the spring repotting, gently separate the clumps, making sure each piece carries a section of rhizome and a few roots, then repot them. Establishment is reliable.

Leaflet cuttings are possible but very slow: detach a leaflet with a small piece of its base, let the cut dry for a day, plant it in a barely moist free-draining mix, and arm yourself with patience. It often takes several months for a tiny rhizome to form beneath the surface before a new stem appears. It is an exercise in patience more than a method in a hurry.

Toxicity

The whole plant contains calcium oxalate crystals. Chewed, a leaf strongly irritates the mouth and throat; the sap can irritate skin and eyes. Keep the ZZ plant out of reach of cats, dogs and young children, and rinse your hands after handling it.

Month-by-month care calendar

Green Hub tips

• The underground rhizome is a water reserve: the ZZ plant fears overwatering far more than a long spell of neglect. When in doubt, do not water.
• In winter, a single monthly watering is enough. At rest and in the low light of the dark season, the plant consumes almost nothing.
• Stems that yellow and soften at the base signal a rotting rhizome: stop watering and check the roots without delay.
• Dust the leaflets with a damp cloth to keep their glossy shine, without a leaf-shine product.