PlantTreat the rhizomes as the plant’s water tank: water a ZZ only when the mix is dry through most of the pot, which in winter can mean once every 4–6 weeks.
A drought specialist from East Africa
Zamioculcas zamiifolia (Araceae) grows wild in eastern Africa, from Kenya south to South Africa, in places with a long dry season. It survives drought on potato-like underground rhizomes and swollen stalk bases that store water and starch. In a severe dry spell it drops its leaflets and waits it out underground.
What look like branching stems are single compound leaves rising straight from the rhizome, each carrying glossy leaflets. New ones arrive in flushes, often several at once, followed by months of apparent inactivity. Both traits point the same way: a ZZ needs far less water than its size suggests, and a quiet period is not a problem to be fixed.
Light and temperature
A ZZ survives at 500–1,000 lux in an office under ceiling lights, which is why it is so popular. It will not grow much there. At 5,000–15,000 lux, such as near an east window or a few metres from a south window, it pushes more and sturdier flushes. Unfiltered afternoon sun yellows and scorches the leaflets.
In weak or one-sided light the stems lean and can flop; give the pot a quarter turn each month. Keep it at 18–27 °C (65–80 °F). It tolerates down to about 10 °C (50 °F) if the mix is dry, and ordinary indoor humidity of 30–60% is fine.
Watering the rhizome, not the leaves
Water only when the mix is dry through 75–100% of the pot. In summer that is typically every 2–4 weeks; in winter, every 4–6 weeks. A skewer pushed to the bottom tells you more than the surface does. When you water, soak the whole root ball until it drains and never leave water standing in a cachepot.
Use a succulent mix, or potting mix with 40–50% pumice or perlite. Rhizomes eventually swell enough to bulge or split plastic nursery pots, which is the usual signal to repot, every 2–3 years in spring. Go 2–5 cm wider and keep the rhizome tops just below the surface, at the same depth as before. Feed two or three times between spring and late summer with a balanced fertilizer at half strength.
Propagation: patience required
Division is fastest. At repotting, pull or cut the rhizome clump into sections, each with at least one stem and its own roots, and pot them into dry mix. Wait about a week before the first watering so any damaged tissue can seal.
Single leaflets root too. Push the base of a leaflet 1 cm into damp gritty mix or stand it in water; it forms roots and a small rhizome over 1–3 months, but the first new stem often takes 6–12 months. Whole stem cuttings root faster and are worth trying from any stem broken during repotting.
Warning signs and safety
The one serious risk to a ZZ is overwatering, and it shows in a predictable way. Yellowing on several stems at once, with mix that has stayed wet, means the rhizomes are rotting: unpot, cut back to firm, pale tissue, let the cuts dry, and replant in dry mix. A single older stem yellowing while the rest stays glossy is normal turnover. Heavy leaflet drop with a bone-dry pot is drought or cold; leaning, stretched stems mean too little light.
ZZ contains calcium oxalate crystals. The ASPCA lists it as toxic to cats and dogs, and the sap can irritate skin, so wear gloves when dividing. A PlantPal reminder works well here, since most checks end with deciding not to water today.
- Light: tolerates 500–1,000 lux; grows best at 5,000–15,000 lux
- Water: when 75–100% of the mix is dry; every 4–6 weeks in winter
- Temperature: 18–27 °C, minimum about 10 °C when dry
- Mix: potting mix with 40–50% pumice or perlite
- Repot: every 2–3 years, when rhizomes crowd the pot
