Long petioles lined with glossy leaflets, beads of sap at the tips, and older stems that yellow off once their year is up: the ZZ plant (Zamioculcas zamiifolia) is close to unkillable, which is why it turns up in so many hallways. Give it light from above and let the soil dry between waterings, and it stays upright and keeps shooting.
Short summary:
Single stem drying out – normal
Stems falling over – lack of light
Drops on leaf tips – guttation
Yellow – overwatering or chlorosis
Curly leaves – scale or mealybugs, rarely spider mite
So just in case, here are the main problems you might meet when caring for your ZZ plant!
Also, indoor ZZ will generally have less problems than outdoor Zamioculcas (except for overwatering; houseplants are often overwatered).
Most ZZ plant complaints come down to a handful of symptoms, and several of them are not faults at all. Use this table to work out whether what you are seeing needs action or simply patience.
| Symptom | Likely cause | Normal or a problem? | What to do |
|---|---|---|---|
| Whole plant turning yellow | Root rot from overwatering and poor drainage | Problem | Water only when the soil is dry, empty the saucer, repot with one-third river sand |
| Yellowing with veins staying green | Chlorosis, a nutrient deficiency | Problem | Feed with leaf-plant fertiliser once a fortnight in the growing season |
| One older stem yellowing and drying | Ageing; nutrients being recycled to the roots | Normal | Leave it, or cut it once fully dried out |
| Stems drooping and fanning out | Too little light, or a pot that is too small | Normal in low light | Move to a spot lit from above, stake loosely, or repot into a larger pot |
| No new leaves appearing | Low light, cold rooms or temperature swings | Problem | Give bright indirect light and keep the pot away from cold glass and draughts |
| Drops of sap at leaf tips | Guttation from root pressure | Normal | Nothing, but rinse and wipe leaves if hard water leaves white mineral spots |
| Leaves curling up | Scale insects, spider mites or mealybugs | Problem | Look for tiny webs or cottony patches and treat the infestation |
Once you have named the symptom, the sections below give the full treatment for each.
If the entire ZZ plant is yellow, it may be due to:
The last possibility is when a new frond or leaf starts growing that is yellow, white or variegated. This is rare. It is a kind of mutation that occurs naturally, like the black ZZ raven.
Usually these are considered valuable and you will surely find amateurs! Try to propagate it when it has grown a bit more.
It’s hard to kill a ZZ plant, but if there isn’t much light, it won’t grow very much. Lack of light is the main cause of slow growth. Find a place in the house that is a little more exposed.
If you’re quite sure your plant is getting enough light, then check on watering and temperature swings. These are also known to block ZZ plant from sending out new shoots.
New growth on a ZZ plant emerges as a pointed spear pushing straight up from the soil, never as leaflets on an existing stem.
A spear can take several weeks to unfurl its leaflets, so resist watering more in the hope of hurrying it.
Growth stalls when the room falls below around 15°C (59°F), so shift the pot away from cold windowpanes and draughty doorways.
Bright indirect light restarts growth, but hours of direct midday sun through glass will scorch the leaflets instead.
It’s normal for older stems or fronds to turn yellow and die, having served their time and been replaced.
This is a normal step in the ZZ plant’s life. Stems last for up to a year. In very favorable environments, a stem can even survive for 2 years. However, as time passes, the plant sends new shoots out. Older stems are less efficient and they wilt away. The yellowing is a sign that nutrients are being brought back into the roots, a form of recycling.
Only cut the stem when it’s fully dried out if you want to help your plant grow more and faster.
It’s also ok to cut it when not fully dry, the plant won’t complain. After all, it is an ornamental houseplant that has the duty to look good!
More often than not, ZZ plant fronds start drooping down. ZZ stems fall over. The long petioles which carry the leaflets don’t stand upright anymore and fan out.
What can you do to make your ZZ plant grow straight again?
Another possible cause is that the pot is too small. Repot into a larger pot.
This is normal, it’s the sign of a happy, well-watered specimen. It’s called guttation or weeping leaves.
This occurs in perfectly healthy plants. Their powerful root system keeps pumping water up to the plants. To release pressure, small pores open on leaves. Excess water leaches out and gathers at the tip.
Also, unneeded nutrients and, eventually, debris from bacteria or dead cells are also evacuated.
If you water with tap water or hard water that has lots of minerals, white spots will appear. Excess minerals are also expelled, and they gather when guttation fluid dries out. In the long term, this can damage the leaves. Indeed, these form corrosive salt mounds. To clean these, simply rinse the plant and wipe it with a soft cloth.
This is rare, and mostly only happens when pest populations are high. Scale insects and/or spider mites infest leaves and suck sap from it.
They leave tiny webs as proof of their presence. In the case of mealybugs, a small cottony substance appears.
Here is an article on how to deal with scale insects on a ZZ plant.
Check the leaflet undersides and the base of each stem first.
