How to grow and care for a ZZ plant

How to care for a ZZ plant

Watering

Less is more with the ZZ plant, so rehydrate the soil only once it has fully dried and been dry for around four weeks, all year round. Never water its compost while it's still moist, as this will likely lead to root rot.

The best method of irrigation is by flushing the compost. This means you keep pouring water into the pot until it comes out of the drainage holes at the bottom. Once this happens, simply stop watering and allow the compost to continue draining for ten minutes (such as on a draining rack), before placing it back in its original location.

Light and location

It's true that ZZ plants will grow in almost all light levels in a home, but the rates of growth will drop significantly in darker locations. If you're aiming for a plant that grows quickly and reliably, keep your ZZ plant within 2m of a window, or even on a windowsill as long as it's not too sunny. ZZ plants can tolerate some sunlight, but ensure it doesn't receive more than three hours per days as too much can scorch the leaves.

Compost and fertilisers

Use a peat–free cactus and succulent compost. Avoid using generic house plant compost as these are tailored more for tropical, moisture-loving plants.

There's no real need to feed your ZZ plant but for best results, apply a light liquid feed of house plant fertiliser, every three months.

Temperature and humidity

Keep your ZZ plant in a room with temperatures consistently above 10ºC. Average house humidity is fine for a ZZ plant.

Pruning

Prune off dying petioles (leaf stems) once all of the leaves have become yellow, to improve the appearance of your ZZ plant.

Staking

Staking isn't necessary. If, however, the plant is leaning to one side, try increasing the light levels by placing it in a brighter spot, with no more than three hours of direct sunlight per day.

How to repot a ZZ plant

ZZ plant does best in pot-bound conditions, so repotting must be done only every two years.

1. When it's time for a repot, water your ZZ plant around twelve hours beforehand, to minimise transplant shock. Choose a pot the next size up from the original. Consider using a transparent orchid pot, which provides better airflow around the root system. This could significantly reduce the risk of your ZZ plant developing root rot as it will help the compost dry out quickly.
2. Using a peat-free, cactus and succulent compost, fill the bottom fifth of the new pot and rest the plant's rootball on top, to check it's at the right level, so it doesn't sit deeper in the compost than it did in its original pot.
3. When you're happy with the level, fill the remaining gaps between the roots and pot's inside edge with more potting mix. Tap the pot's side a few times to knock the soil into place and remove any air significant pockets, while leaving smaller ones to aerate the rootball, instead of squishing and suffocating them.

How to propagate a ZZ plant

Propagating a ZZ plant is fun, but will take time to see results. The best way to clone your plant is via leaf cuttings.

1. Choose three of the largest mature leaves from your ZZ plant, ensuring they have no signs of disease or damage.
2. Cut the leaves off the plant, ensuring the whole petiole of each leaf is attached – the roots will develop from the base of each petiole.
3. Let each petiole wound callous over by keeping the leaves on dry tissue paper for twenty four hours, ideally in a dark cupboard.
4. Place the cuttings in a jar with water, ensuring only the bottom third of the leaves (wound-end down) are submerged. Keep the cuttings on a bright, sunless windowsill to speed up rooting times.
5. Change the water every four days to prevent rot, using lukewarm water to avoid shocking the plantlets.
6. Roots may take up to four months to appear, so be patient. Once the first roots are 3cm in size, plant the cuttings up individually into 7cm post filled with house plant compost. Water once every four weeks and continue to keep them in bright spot out of direct sunlight. New leaves can take up to six months to grow.

Common issues (how to diagnose problems)

Yellowing leaves is a natural behaviour of a healthy ZZ plant. If, however, multiple stems are yellowing at once, take a look at the root system for signs of root rot (see below).

Curling and yellowing leaves or brown shoots are signs of dehydration, but could also be a sign of root rot. Push your finger into the compost to feel the tuber. If the tuber is soft or wrinkled, this means it's dehydrated, which could either be from a lack of water or too much water, which caused the roots to rot and therefore cut off the source of moisture to the tuber. Take the plant out of the pot and remove any dead roots, which are soft, brown and come away from the plant easily. Keep any healthy roots intact. If more than 50 per cent of the roots are rotten, repot the plant into a smaller pot to keep the rootball tight. If less than half of the roots have rotted, repot it back into the same pot and fill the remaining gaps with fresh cactus compost. If there are not rotten roots and the compost is completely dry, simply water your ZZ plant to rehydrate the tuber.

Small black flies that hover around the soil are fungus gnats, which breed in moist soil. This means you are watering your ZZ plant too much. Rehydrate the compost only once the soil has dried out and been dry for at least four weeks. The gnats do best in moist compost so should disappear as the compost dried out.

A lack of new growth can be down to low light, but remember that ZZ plants are naturally slow growing.

Toxicity

The ZZ plant is classified poisonous to humans or pets when eaten.

Varieties to grow

Zamioculcas zamiifolia – the most common type of ZZ plant currently grown for sale. It boasts waxy green leaves with plump stems that will turn dark green over time. Height x Spread: 1m x 80cm
Zamioculcas zamiifolia 'Raven' – grows to a similar size of a non-variegated ZZ plant, but this plant will sport a deep black appearance that will contrast well sitting next to brighter-coloured plants on a window, for example. H x S: 1m x 80cm

Frequently asked questions

What is so special about a ZZ plant?

ZZ plants are regarded as one of the favourites in the house plant industry because they're easy to care for. The plant will withstand neglect with watering or feeding, and will still look just as good as when it was bought.

Is a ZZ plant toxic to cats?

Yes, unfortunately ZZ plants are poisonous to cats and dogs, and humans, too.

What are the disadvantages of the ZZ plant?

Two disadvantages is that the plant is a slow grower, meaning it will only produce two new shoots per year, maximum. Another downside to the zz plant is that it's poisonous to humans and other animals when digested.

What does an overwatered ZZ plant look like?

The soil will feel moist all the time and will smell 'earthy'. The stem will be loose in the potting mix, meaning it will feel wobbly when handled. The leaves may also turn yellow or brown after a few weeks.

Why do ZZ plant leaves turn yellow?

It's natural for a ZZ plant to have yellowing leaves from time to time, especially when its the older leaves (those that have been on the plant the longest. If, however, your plant is suddenly becoming yellow, check the root system and the tuber (its bulb) that'll sit around 2-5cm below the soil line. If the tuber is soft and squishy, this indicates root rot (hard potato-like tubers are fine, and indicate that the plant isn't in enough light or warmth).

Are ZZ plants easy to keep alive?

ZZ plants are some of the easiest house plants to grow due to their tolerance to infrequent watering.

Where is the best place to put a ZZ plant?

Although ZZ plants tolerate low light levels, they do best in bright, indirect light. So, for best results, keep yours within 1.5m of a north- or west-facing window, ideally on the windowsill. Avoid south- or east-facing windowsills as they suffer with too much sunlight.

Varieties of ZZ plant to grow

• Zamioculcas zamiifolia 'Raven' – a new variety. The new leaves are a fresh green and deepen to almost black.
  Height x Spread: 70cm x 50cm