There’s no plant quite as tough as the ZZ Plant (Zamioculcas zamiifolia). They’ll take almost everything you throw at them with grace, but a few exceptions can turn their waxy leaves from luxurious green to dingy brown.
Thankfully, a few brown leaves are not enough to take out these true survivors. The good news is that if you treat the potential cause of the damage, your ZZ will be back to its verdant self again in no time.
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ZZ Plant Overview
|Scientific Name||Zamioculcas zamiifolia|
|Common Names||ZZ Plant, Zanzibar Gem|
|Origin||East Africa, Kenya, South Africa, and Tanzania|
|Size and Dimensions (Mature)||Up to 3 feet for large cultivars (90cm)|
|Distinguishing Features||Glossy dark leaves with thick rhizomes that are pale brown or tan in color|
Why Is My ZZ Plant Turning Brown?
Brown Leaves in ZZ plants are predominately caused by too much water. Other causes include under-watering, too much direct sunlight or sun damage, temperature stress, poor water quality, disease, nutrient deficiency, transplant shock, low humidity, and the action of pests.
Most Common Problems that Cause Brown Leaves On ZZ Plants
The ZZ is an arid zone specialist. The most common reasons for brown leaves reflect some gap between their treatment and the conditions for which they evolved.
Let’s look at how you can close the distance and get your verdant treasure back into top shape.
Too much water is easily the most common cause of brown leaves on a ZZ plant. They struggle to survive if their roots are constantly swamped in boggy soil. These hardy plants need far less water than you’d think, so it’s easy to go overboard.
The ZZ is one of the most drought-tolerant of all the popular indoor plants and prefers dry environments, like succulents . They have a host of thrifty adaptations that help them survive a long time without much moisture. A waxy coat on their leaves keeps them well hydrated no matter how hot or dry their environment becomes.
They store water and nutrients in thick roots called rhizomes. This clever desert adaptation makes them uniquely vulnerable to root rot. The roots need ample oxygen and periods of dryness, or the rhizome will rot.
Over-watered leaves will be brown but have a sodden, floppy quality. The potting soil will also be constantly wet and might even smell unpleasant. A little water truly goes a long way.
Fungus gnats are another giveaway of an over-watered plant. They love moist, decaying potting mix that tends to develop during improper watering.
If you’ve overwatered, start by laying off the watering and letting the root system dry right out.
We also suggest you check that there’s no root rot. Tap the plant free from its pot and take a look. Healthy roots are pale in color and firm to the touch. You’ll be able to spot the rhizomes right away – they’re plump little things that are the same bright cream color as the rest of the root system.
If you’ve caught the problem in time, you need only let the plant dry out.
For more substantial cases, especially those suffering rotten roots, repot the ZZ in loosely textured, well-draining soil in a larger pot with lots of drainage holes. This will allow the excess water to drain and prevent too much water from clogging the pot in the first place.
If you have repeated over-watering problems, I suggest you invest in an electric moisture meter to help prevent you from going overboard in the future.
You truly have to work at under-watering a ZZ plant. Their reputation as a low-maintenance plant species comes from just how long they can go with a very low amount of water.
While they don’t need a lot of water, excess heat or particularly dry conditions results in crisp brown leaf tips or edges. Long periods with a lack of water will damage even this hardy plant. Thankfully, you can reverse even severe water loss with a good thorough soaking.
Watering from below is the best way to get enough moisture into the soil. This involves resting the ZZ Plant’s pot in a tub of clean water with the drainage holes on the bottom of the pot submerged. The water will soak into the soil close to the root mass where it’s needed the most.
To prevent problems moving forward, consider a watering schedule.
Potted Exotics Pro Tip: Spend an hour or two once a week just checking in on your plants and watering those in need. While ZZ plants don’t need much attention, it’s like arranging a brunch date with a leafy friend.
Poor Water Quality
For most of us, tap water is one of the great lifesavers of the modern age. To ZZ plants, it can be a slow and noxious poison.
Many chemicals added to tap water to protect human health, like chlorine or fluoride, will build up in leaves over time and cause damage to the plant’s tissue.
Likewise, the mineral salts found in hard water will collect in the soil and inside the plant itself. This damage is most evident in leaves, where it shows up as curled brown leaf tips and edges.
It’s easy enough to get around. Leave a jug or bowl of water overnight, and most chlorine will evaporate by morning. A cheap filter jug will pull out most mineral salts too.
If you’re feeling indulgent, you can collect rainwater for your green babies or buy distilled water designed for steamers or irons.
ZZ plants are generally pest resistant. That same waxy coat that holds water into the leaf and gives them such a lovely shine is also challenging for insects to get their teeth into.
That said, spider mites and mealy bugs don’t mind taking a nibble if the opportunity arises.
Damage from insect pests can vary, but spider mites leave blotchy brown patches where they dine.
Mealybugs can cause the leaf to brown from the tip down. They suck the sap from the leaf’s veins, starving the tissue further up the leaf from their bite. The result? A dead leaf and a fat and happy pest!
If you spot pests, the best solution is to give the ZZ a wipe-down with a bit of neem oil. The waxy green leaves of the ZZ are not a particularly nourishing meal, so it won’t take much to kill them off. But it’s absolutely a sign you should check any other plants nearby.
These obnoxious visitors love to jump from one plant to the next, so if they’ve wound up on an unappealing ZZ, they’re likely gorging on a more delicious houseplant nearby.
Too Much Direct Sunlight
One of the reasons the ZZs make such great house plants is that they are very good at making use of low light.
Too much light – especially direct sunlight – and they’ll develop sunburn. This sort of browning appears in large patches on the side of the plant closest to its light source. It’ll dry out and often breaks away, leaving holes in the leaf where the crispy spots once were.
Correcting this is thankfully easy. Relocate your ZZ away from sunbeams and bright light. Consider an east-facing window to avoid harsh afternoon sun.
Though they can tolerate low-light conditions, new growth requires bright, indirect light, so move them to a brighter location if needed.
Lack of Humidity
ZZ plants thrive in humid environments that mimic the forests of their natural range. Unfortunately for them, the average living room is hardly a sweltering tropical paradise. Typically indoor environments have dry air that sits around 20% humidity or less. ZZ plants prefer humidity levels between 40 and 50%.
There are a few tricks to edging the humidity around your plants that little bit higher.
A pebble tray is a serviceable homemade option. This is a shallow tray or pan of river stones and water. Enough water evaporates over time to create a gentle humidity in the surrounding air.
You can also cut to the chase with an electric humidifier.
We don’t recommend misting your ZZ plants, especially with a spray bottle of tap water. This can leave unsightly marks on the leaves as the water dries. It’s also of limited use as it only briefly raises the humidity around the plant and won’t correct the overall problem.
The ZZ plant is not a frail beauty and generally shrugs off disease without much fuss. The two to watch for are fungal rusts and bacterial leaf spot.
Plant rust is one of the most common fungal diseases and is caused by a huge variety of fungal pathogens. It causes golden or ruddy speckles that do indeed resemble rust. It’s rarely fatal, but you can treat it with a copper-based fungicide.
Bacterial Leaf Spot appears as neat brown or black spots that may have a golden ring around them. The affected area inside the brown spots often rots away, leaving neat little punctures in the leaves. Like rust, there’s a heap of different culprits, so it can be hard to treat.
Commercial, all-purpose plant medicine can help, but the best practices are moving the plant to quarantine and letting the ZZ shrug it off without further intervention.
Different nutrient deficiencies show different signs of struggle, but a lack of some nutrients under the right conditions can fuel brown leaves on a ZZ Plant. If you are worried about nutrient deficiency, consider replanting your ZZ in a new pot with fresh soil and fertilizer.
Try to grow a tropical plant like a ZZ in cold temperatures, and you’ll face dead leaves and drama.
Chilly plants can throw yellow leaves in protest that will eventually turn brown and drop off, starting with the older leaves first. Cold drafts can also damage the plant’s health.
That said, it’s possible to have too much of a good thing. Prolonged periods of heat can stress the ZZ in much the same way as underwatering. Leaves will crisp up from the tips and edges inwards and eventually drop off.
Aim to keep your ZZ between 65-90°F (18-32°C). They’ll put up with high temperatures out of that range for short periods, but much below 50°F (10°C) will result in frost damage.
Every time you move a ZZ plant to a new pot, it causes damage. Even gentle handling will damage the fine outer roots and cause brown tips. If your care is otherwise sound and you have brown leaves in the weeks after a repotting, it’s likely your brown leaves are from transplant shock.
It often looks like dehydration because, in essence, it is precisely that. Damaged and stressed roots can’t get the moisture from the soil up to the rest of the plant.
If you watered the ZZ during the repotting, it’s best to resist the urge to water again. Your best tactic here is patience. Just wait it out. ZZ plants can be slow growers. It might be a while before you see a response. But in time, it’ll start popping out those bright new leaves.
How to Keep A ZZ Plant Healthy
A ZZ plant is a truly low maintenance plant. To keep them at their best, consider the following:
- Water only when the soil has dried out.
- Provide good drainage with loose soil and a pot with drainage holes.
- Maintain temperatures between 65-90°F (18-32°C).
- Provide enough light. They will survive in low light, but bright indirect light is best.
Other Frequently Asked Questions
How Often Should You Water a ZZ Plant?
Water your ZZ plant when the soil has dried out almost entirely. In the summer, this may be twice a month. You may go the whole winter and only need to water once – or not at all!
How Do I Bring My ZZ Plant Back to Life?
Start by repotting in fresh soil and watering well. Take a good look at the roots and remove any that are rotten or dried out to the point of being brittle. Place it in an area with ample light away from direct sunlight, and wait.
ZZ plants are slow growers at the best of times. It could take a while, but if there’s life there, it will eventually show itself.
Why Are My ZZ Plant Leaves Turning Yellow?
Most often, ZZ Plant’s leaves turn yellow due to overwatering. Yellow leaves are usually the beginning stage of the leaves turning brown, and while overwatering is the primary culprit, all the above-listed reasons can also contribute to the problem.
How to Tell If a ZZ Plant is Over-Watered or Under-Watered?
An over-watered ZZ plant:
1. Has soft brown leaves that are discolored across the whole leaf
2. Has soil that is always wet, and that smells foul
3. May have rotten roots that are slimy to the touch or disintegrate when handled
4. May have fungus gnats breeding in its soil
An under-watered ZZ plant, on the other hand:
1. Has crisp leaves that start brown at the tip and edges
2. Drops otherwise healthy leaves
3. Is loose in the pot
4. Does not smell or have pests
Get a grip on the differences, and you’ll be able to work out the best tactic to revive your brown-leafed ZZ plant.