Written from the home-garden experience of Shami, who has grown plants for 8+ years in Malappuram, Kerala. All photos are our own.
ZZ plant is honestly one of my favourite outdoor plants. It doesn't need much care, and its highlight is the waxy leaf, which gives it a plastic-like look. It's usually a problem-free plant, but if you give it too much care, it will die. That means over-watering, too much sun, and so on.
The yellow leaf problem
The main issue I've seen with this plant is leaves turning yellow. It comes from over-watering. Another sign of over-watering is black spots at the nodes of the leaves and on the leaf stalks.
If you see a yellow leaf, cut it off before it stresses the whole plant. And always check how dry the soil is before you water.
A plant with no stem
ZZ plant (Zamioculcas zamiifolia) is a stemless plant, in the arum family, originally from eastern Africa. It grows from a bulb-like thing underground, the rhizome. What looks like a stem is actually a leaf stalk (a petiole), with the leaflets arranged along it.
Sometimes a stalk dries up. Don't panic: after some time, a new one grows from the rhizome.
The varieties I know of
- Green: the leaf is full green.
- Black ZZ: the leaf has a black shade. When it's young it's green, but as it matures it turns black.
- Dwarf ZZ: it doesn't grow tall. It's bushy, and the leaves are a little rolled up.
- Variegated ZZ: there's a white shade in the green leaf.
The glossy leaf
The leaves are very thick, very glossy and plastic-like.
You'll often hear that ZZ plant is a good air purifier, and that's a big reason many people choose it indoors. The claim comes from a 1989 NASA sealed-chamber experiment. Later research found that houseplants do very little for the air in a real, ventilated home, so I'd choose this plant for its looks and its easy nature.
Keeping the leaves clean
- Small plants: take a piece of lemon, or some vinegar, and mix it with the same amount of water. Dip a cotton pad in it and wipe the leaves. Test it on one leaf first.
- Big plants: wiping isn't practical, so I use a shower and give the leaves a little bath. In summer, once a week is good.
- Rainy season: put the plant in the open rain for a short while, then move it back to shade.
Potting mix and pot size
The potting mix needs to be very loose, so water flows through it easily. I use soil, some cocopeat, and some cow dung powder. If you have lake sand and perlite, you can add those too. They're optional, but better.
Never plant a small plant in a big pot. Always choose a pot that fits the size of the plant. Start with a small pot, and when new shoots or branches come and the pot gets crowded, repot into the next size up. Keep going step by step, increasing the pot size each time.
Watering
I can't give you one fixed day, because it depends on the amount of potting mix. If you use a good amount of cocopeat in the mix, you can water about once a week. Always check that the soil is dry before watering, and make sure the water flows out properly.
Feeding
This plant grows slowly and doesn't need much fertilizer. I give it once a month. I put cow dung powder or vermicompost at the sides of the pot, and I never touch the leaf stalks when I do. These work too:
- Soaked soya water.
- Cow dung and rice gruel water (kanji vellam): mix the two, ferment, dilute, and pour.
- Fermented peanut cake water: it's fermented after about 1 week.
The last two have a smell that many of us don't like, so I mainly use the soaked soya water, or NPK 19:19:19 (dose as directed on the product label).
Making new plants
Petiole cuttings (my recommended method): choose a healthy parent plant and cut the leaf stalks from it. You can plant them in soil or in water. In soil, keep them in shade, and you'll see roots in a month. In water, dip the stalks in a glass and change the water every week, and roots come within a month.
Single leaf: cut the leaf with the bottom part of it and place it in a Jiffy (a small coco peat pellet), where roots grow faster. You can buy Jiffy pellets online or at garden shops. I've even tried planting a yellowish, almost dead leaf in a Jiffy, and it had roots coming after several days. But with this method the growth is very slow, and the plant ends up a bit smaller, so petiole cuttings are the method I'd suggest.
A note on safety
I've read that ZZ plant is toxic, and that's correct. It contains calcium oxalate crystals, which are mildly toxic to people and pets if chewed. The sap from broken leaves or stalks can irritate skin in some people. Keep it out of reach of pets and children, and wash your hands after pruning or handling it.
It's a beautiful plant that needs very little care, and a good one to start with.