ZZ plant is a stemless, herbaceous perennial that has found a foothold in homes in recent years because of its ability to tolerate low light, drought, and to make anyone look like they have a green thumb by resisting pests and diseases.
ZZ plant (Zamioculcas zamiifolia), also known as Zanzibar gem, zuzu, eternity plant, or aroid palm, these plants are native to Eastern Africa, where they grow in arid, rocky, warm regions. You’ll find them growing indigenously as far south as South Africa and as far north as Kenya.
Originally classified as Caladium zamiifolia, they were later reclassified as Z. zamiifolia. They are the only species within the Zamioculcas genus.
The plant has thick, fleshy petioles holding alternate, ovate-elliptic pinnate leaves. Depending on the cultivar, the leaves might be medium green with or without cream, to nearly black, but always thick and glossy.
In the summer, mature plants produce an inflorescence that consists of a modified bract inside a green spadix, with bronze, yellow, or white petals. The inflorescences somewhat resemble those on a peace lily (Spathiphyllum spp.) and rarely appear on plants grown indoors.
The plants typically grow about three feet indoors.
- Genus: Zamioculcas
- Species: zamiifolia
- Native To: Eastern Africa
- Sun Exposure: Typically bright indirect or diffused light
- Soil Preference: Loose, chunky loam
- Soil pH: 6.0-7.0
- Height: 3 feet
- Toxicity: Toxic when eaten, skin irritant
Caring for ZZ Plant:
ZZ plants do best in warm environments with moderate humidity. They can tolerate temperatures between 45-100°F, but they grow best in temperatures between 60-90°F. Anything below 40°F will damage or even kill them.
Relative humidity should be between 50-100%, though they will tolerate lower humidity levels. Avoid placing them near drying HVAC vents or open windows. If your interior lacks the necessary humidity, you can group plants together or use a small humidifier.
Rock trays and spraying the plant manually generally aren’t reliable methods of raising relative humidity, so don’t waste your time with these techniques.
Light
Although they’re tropical plants that need heat to survive, they don’t tolerate direct light. The plants have developed long-lived leaves that are known to survive up to six months without light and won’t suffer any harm. They can’t remain in dark, though, or they will eventually stop producing new growth.
Having said that, bright, indirect light is ideal. That translates to something like a few feet away from an east, west, or south-facing window covered in sheer curtains. A few feet to the side of a west-facing window without curtains would work as well. Just double-check that the plant is never in direct light as the direction of the sunlight moves throughout the day.
On the other end of the spectrum, low light is fine. These plants are known to thrive in basements, offices, or windowless rooms, so long as there is fluorescent lighting to provide some light.
How dark is too dark? It’s a little hard to tell since the plant is so adaptable. If it fails to produce any new growth after a year or two, move it into brighter lighting and see if it starts developing new petioles. However, these plants have shown that they can develop new growth in conditions as dark as 25-foot candles, while most houseplants require close to 100-foot candles to thrive.
Soil
In their native environment, ZZ plants grow in rocky, sandy ground. In a container in the home, they will thrive in any mixture of sphagnum moss, perlite or vermiculite, bark, coco coir, rice hulls, and loam. The important characteristic is that the medium is chunky.
There are many commercial potting mixes on the market that are suitable, or you can make your own.
If you can’t find a commercial potting mix that fits the bill and you don’t feel confident building your own, combine one part cactus mix and one part standard potting soil.
Water
ZZ plants have large, rhizomatous roots that allow them to store water. They can go a long while without watering but are sensitive to standing water around their roots.
Consider that in their native environment, they grow in arid, xeric landscapes with rocky, sandy soil with excellent drainage, and you can see why they developed an effective storage system. You can also understand why they don’t fare well with wet feet.
When you water, only do so when the soil has dried out completely. If you insert a finger as deep as you can into the soil, it should feel dry. At that point, add a small amount of water until the soil feels barely moist all the way through.
If you imagine the moisture content of a sponge that you have wrung out thoroughly, that’s what you’re aiming for. When the soil feels this level of moisture, you’ve watered the right amount.
Don’t add more water until the soil has completely dried out. This might mean you’re only watering once or twice a month. If in doubt, err on the side of caution and water less often than you think you need. It’s easier to overwater than underwater this plant.
During periods of extreme drought, the leaves will drop from the plant, leaving behind the petiole. This is a defense mechanism that allows the plant to survive an extended lack of moisture. If the leaves start dropping from your plant and the soil is dry, it’s a good indication that you need to provide your plant with additional water.
Dropping leaves that are mushy and black, along with moist soil, is an indication that you’re overwatering.
If all this sounds a bit complicated, a moisture meter is a useful tool in helping you determine precisely how dry the soil is. Only water when the soil registers as completely dry, and then stop when it registers as moderately moist, not wet.
Feeding
Typically, feeding Zanzibar gems isn’t necessary. They get all the nutrients they need from the soil, provided that you are changing out the potting soil every few years. We’ll talk about the importance of this in just a bit.
However, young plants can be fed with a mild houseplant fertilizer with an NPK of 1-1-1 or 2-2-2 once in the spring to encourage new growth.
Maintaining
The glossy leaves on this plant look like they’ve been painted with clear nail polish. The glossy coating isn’t just an aesthetic development. The glossy coating helps reduce transpiration and allows the plant to conserve water.
When dust develops on the plant, it limits the plant’s ability to complete respiration and gather light to photosynthesize. Wipe the leaves regularly with a damp cloth to remove dust.
Every few years, empty the growing container and replace it with fresh, new soil. This is necessary because soil tends to become depleted and compacted over time. Compacted soil leads to root rot.
If your plant is in low light, it might become leggy. Feel free to prune off any leggy growth, though leaving it won’t hurt the plant. Always remove broken or discolored growth. Plants won’t branch where you cut, so either cut back to the ground or to the nearest leaf.
Upgrade the container to the next size up once the rhizome takes up three-fourths of the container.
When working with the plant, wear gloves if you’re sensitive to calcium oxalate. The plant exudes a milky latex that contains calcium oxalate when cut, and this substance is known to irritate some people.
Best Species and Cultivars
For several decades, only the species plant was available to home growers, but in recent years, many new cultivars have been developed. ‘Raven’ is one of the most popular, with its dark foliage. About 20 years ago, a variegated plant was found and has been used to produce several cultivars. Expect to see more of these on the market in the future.
Raven
Also sold as ‘Dowon,’ this cultivar has dark green or black leaves that emerge as light green before darkening as they age.
Supernova
‘Supernova’ looks similar to ‘Raven,’ with black or deep green leaves. The difference is that the plant itself stays a bit smaller, topping out at about 18 inches, and the leaves are smaller, as well.
Variegated
Currently, there are several unnamed variegated cultivars on the market. Be aware that many of these aren’t stable and might revert to a solid form. You should remove any solid growth. All-white or all-yellow leaves should be removed as well.
Zamicro
‘Zamicro’ stays under two feet tall with smaller leaves than the species. There are also more of them.
Zenzi
‘Zenzi’ is a more petite option, growing only to about a foot tall. The leaves are also closer together.
Propagation
ZZ plants are readily propagated through leaf cuttings, petiole cuttings, and by dividing the rhizomes.
Choose a petiole about four inches in length, or select a single, healthy leaf and cut it at the base. Leaf cuttings are quicker to root because roots don’t form until the entire cut has callused over. Petioles cuttings have more tissue that must callus over before the roots can form. However, petiole cuttings tend to take more readily and grow more quickly once they callus.
Don’t plant the cutting for 12 hours to allow the callus to begin to develop.
Place the cuttings in four-inch containers filled with potting soil as described above. Press the cuttings into the soil so they stand upright on their own and keep the soil moist as the rhizomes develop, which can take several months. Place the cuttings in bright, indirect light.
Occasionally dig down into the soil gently and look for rhizome development. Once you see a rhizome forming, allow the top inch of soil to dry out between watering. After a few months, you can transplant it into a larger container and water as normal.
To divide a ZZ plant, remove it from the container and gently brush away as much of the soil as you can. Identify the individual rhizomes, which look like tubers. Using a sharp, clean knife, gently separate the tubers. Plant each one in its own individual pot and grow as normal.
Common Problems, Pests, and Diseases
ZZ plants are rarely troubled by pests or disease. Stressed plants might be infested by aphids or spider mites. If you identify either on your plant, you can treat them using neem oil or insecticidal soap. You can also place the plants in a bathtub or shower and spray them with water to knock the insects loose. Repeat this weekly until they are gone.
Isolate the plants while you’re treating them to avoid spreading the pests.
The only disease that you might encounter is actually a physiological condition known as root rot. This occurs when the plant is given too much water, and the roots essentially drown. Overwatered roots are deprived of oxygen, and they rapidly begin to die.
When this happens, the upper parts of the plant will droop, and the leaves will turn mushy and fall from the plant. If you notice these symptoms, remove the plant from the container and replace the soil. Then, check that the pot’s drainage is unclogged. Finally, repot the plant and reduce your watering schedule.
