The reason for a dying ZZ plant is usually because of root rot due to overwatering and slow-draining soils. ZZ plants are drought-resistant and require the top 2 inches of soil to dry out between bouts of watering. If the soil is consistently damp the ZZ plant’s bulbs rot which causes the leaves to turn yellow and die.
ZZ plants need bright, indirect to thrive and should be turned occasionally to maintain even growth as they can grow leggy with a drooping appearance if they do have enough light.
If the ZZ plant’s leaves are turning brown, this is usually because they are exposed to temperatures cooler than 55°F (12°C) or they are in too much direct sunlight.
Keep Reading to learn why your ZZ plant (Zamioculcas zamiifolia aka emerald palm) is dying and how to implement the solutions to revive it…
ZZ Plant Turning Yellow? (Overwatering)
- Symptoms. Yellowing leaves and drooping branches.
- Causes. Overwatering, slow draining, or compacted soils or pots without drainage holes in the base.
The ZZ plant is native to East Africa with a significant swathe of its native territory lying in the seasonally arid regions of Kenya. Therefore the ZZ plant has several significant adaptions to tolerating drought-like conditions, similar to succulents such as aloe vera.
These include waxy, relatively small leaves with the aim to reduce the surface area for transpiration (water loss) in arid climates and high temperatures and fleshy rhizomes that store water.
The branches are also relatively thick and fleshy as they are used for storing moisture reserves as a survival strategy during times of drought.
As ZZ plants have significant adaptions for dry conditions, the ZZ plant is particularly sensitive to overwatering, damp soils without a poor structure, and any standing water in saucers and trays underneath the pot which keeps the potting intolerably damp for the ZZ plant to survive.
Damp soil causes the ZZ plant’s rhizomes to rot and prevents the roots from uptaking nutrients and moisture (due to decreased root respiration) which turns the leaves yellow.
The ZZ plant is particularly vulnerable to the effects of overwatering in Winter as the plants go into a state of dormancy due to fewer hours of daylight and therefore require watering much less often, compared to most houseplants.
How to Save a Yellowing ZZ Plant
The key to saving a yellowing ZZ plant is to recreate some of the conditions of its native environment by letting the soil dry before watering, decreasing watering frequency in Winter, and ensuring the ZZ plant is planted in well-draining potting soil.
- Let the top 2 inches of soil dry out between each bout of watering (which typically means water every 2 or 3 weeks) during Spring and Summer. Feel the soil to a finger’s depth to assess when the 2 inches of soil dries out and then water thoroughly. This style of watering replicates the typical drought followed by a deluge (of rainfall) that the ZZ plant typically experiences in its native environment.
- Only water ZZ plants once a month (if that) in the Winter to prevent yellowing leaves. ZZ plants can tolerate drought far better than overwatering, so if in any doubt, skip watering for another week or 2 during Winter and the ZZ plant should be much happier for it.
- If the soil is compacted then repot your ZZ plant into a more porous potting medium. Ordinary potting soils can retain moisture for too long for the ZZ plant to tolerate, which combined with overwatering can cause root rot and yellow leaves. Mix around half ordinary potting soil with half succulent and cacti soil, perlite, or vermiculite. This ensures that the soil stays porous and well draining which mitigates the risk of root rot to prevent any further yellowing of the leaves.
- Check whether your ZZ plant’s pot has blocked drainage holes and empty any saucers, trays, or decorative outer pot of excess water. Good drainage is essential for ZZ plants, so if excess water cannot drain efficiently the the leaves continue to turn yellow and the ZZ plant is likely to die back.
Once the soil has had a chance to dry out properly, the roots can respire more efficiently and the ZZ plant can recover. However, if the soil has boggy for too long then the roots and rhizomes are more likely to be rotting and the ZZ is unlikely to revive.
ZZ Plant Leaning, Drooping, or Growing Leggy (Branches Lean Towards Sunlight)
- Symptoms. The branches droop or lean in one direction.
- Causes. The branches are either looking for more light (due to a deficit) or they are growing to the strongest source of light.
ZZ plants are adapted to growing under the cover of other vegetation, so they can scorch in bright direct light and prefer indirect light.
Whilst ZZ plants are shade tolerant and the leaves can even still stay green in lower light, they grow best in brighter, yet indirect light rather than deep shade.
In deep shade, ZZ plants grow leggy and droop as they search for more light to meet the plant’s energy requirements.
In too much shade the ZZ plant redirects its energy into growth to find light as a survival strategy which often causes the branches to weaken and droop.
Even in brighter conditions, if the ZZ plant stays in the same position then the branches can grow towards the light if the plant is not turned regularly to ensure even exposure to light.
How to Save it…
Once the branches have weakened a drooped significantly, these individual branches typically do not stand up again and recover their appearance.
However, if the ZZ plant’s branches are just leaning or turning leggy then move the ZZ plant to an area of bright indirect light and turn the plant around by 1/4 every week or so, to ensure even exposure to light and more even growth.
Revive ZZ Plants that are not Growing
ZZ plants are naturally very slow growers even if their conditions are optimal and all their growing requirements are finely tuned to thrive.
Its slow growth rate is because the ZZ plant grows in arid, unpredictable climates with often significant drought conditions for months. In fact, ZZ plants have been neglected for 4 months without watering and have not suffered any significant adverse effects.
Slow growth is a way of conserving water in dry climates so that the ZZ plant can thrive in habitats where most plants would struggle.
The ZZ plant also goes into a state of dormancy during Winter in response to lower temperatures and fewer hours of light, in which it does not grow significantly.
ZZ plants are such slow growers that there are studies into how to increase the growth rate of propagated ZZ plants for commercial growers in order to meet consumer demand properly.
To increase the rate of growth of your ZZ plant, locate the plant in a room with bright, indirect light and use an all-purpose houseplant fertilizer at half strength during the Spring and Summer.
ZZ Plant Leaves Turning Brown (Temperatures Cooler than 55°F)
- Symptoms. Leaves turning brown at the tips or brown and yellow.
- Causes. The most common cause is cold temperatures or too much direct light.
ZZ plants are native to warm tropical climates and live in a mild to warm temperature range all year round, and therefore do not tolerate cold temperatures which result in the leaves turning brown.
Indoors the ZZ plant’s preferred temperature range is 75°F to 85°F however it can easily tolerate temperatures outside of this range without adverse effects such as brown leaves.
It is at temperatures below 55°F (12°C) and temperatures higher than 105°F (40°C) that the leaves turn brown as a sign of stress.
When locating your ZZ plant be conscious of draughts and try to avoid contact between the leaves and the cold glass of windows which can be much cooler than the ambient temperature of a room at night.
Once the ZZ plant is moved it should recover. The brown leaves may drop off, however, but there should be new growth in the Spring if the conditions are good.
The leaves can also scorch brown due to too much direct sunlight.
ZZ plants grow under a canopy in dry woodlands in Africa, where they are sheltered from harsh sunlight. Move the ZZ plant to an area of bright indirect light so it can recover.
The scorched leaves do not return to a healthy green again, so wait until you see new growth in the Spring and cut back any brown leaves for aesthetic purposes.
(Read my article on how to grow and care for ZZ plants indoors for all the best care tips).
- A dying ZZ plant is often caused by root rot due to overwatering and slow-draining soils. ZZ plants need the soil to dry between each watering. If the soil is too damp the leaves turn yellow with a dying appearance. ZZ plants turn brown and die in temperatures cooler than 55°F.
- ZZ plants start drooping if they do not have enough light. Whilst ZZ plants can tolerate shade, they often droop and lean towards the strongest sources of light if they are in a particularly poorly lit room. Locate ZZ plants in a room with bright indirect light and turn the plant 90° around every week to ensure even growth.
- ZZ plants have a very slow rate of growth, even during Spring and Summer, and typically do not noticeably grow during their Winter dormancy. Grow ZZ plants in bright, indirect light and use fertilizer at half strength to increase the rate of growth. A slow growth rate is an adaptation to growing in regions of drought stress.