ZZ plants (Zamioculcas zamiifolia) are well-known for enduring neglect, but this does not mean that they are immune to it. I will cover the most typical root rot problem that ZZ plants encounter, as well as how to resolve and prevent it.
Aside from root rot, it is a plant that can be kept for a long time. Root rot is the number one killer of Zz plants, so be cautious.
Here is the steps you can save your ZZ plant from root rot:
- Take out the ZZ plant from its pot.
- Now clean the root system and rhizomes with running water.
- Trimm off the infected roots and rhizomes (brown and mushy)
- Repot the plant into a new container with sterilized soil
- Only water when the 1-2 inches of top soil is dry.
Find out how to tell if your ZZ plant is suffering from root rot in the following section.
Signs of Root Rot in ZZ Plant
Most of the signs and symptoms of plant diseases look similar. If you are unfamiliar, you’re most likely to mistake one for the other. The key to properly diagnose the signs of root rot is to look for the distinct changes that are happening in your Zz plant.
Here are the common signs you can observe. If you see most of these, then it’s time that you take serious actions to prevent your Zz plant from dying.
Loss of Vigor
A Zz plant that is afflicted with root rot will grow at a slow rate. There will be little growth in size, and the plant will grow slowly, making it more susceptible to disease.
Your Zz plant will generally look unhealthy. If you noticed that your Zz plant is taking too long to grow, then root rot is a possibility.
Leaves Turning Brown
It’s either you see large brown spots in the leaves or the entire leaves themselves are turning brown.
That condition is often a result of root rot. One distinguishing factor to observe is that the leaves are often mushy when touched.
Once you check the stem a few inches above the soil, you’ll notice there that the stem is also rotting. Once the roots are severely damaged, the stems will also suffer.
Stem rot is characterized by being soft and slimy. Once you try to move the base of the plant, it will easily detach leaving the roots behind the soil.
Yellowing and Wilting
If the leaves start turning yellow from the bottom to the top, there’s a high chance that the roots are already rotting.
The yellowing is first to manifest due to the lack of water and nutrients channeled from the soil. The whole Zz plant will then start wilting.
The surest way to confirm whether your Zz plant is suffering from root rot is to check the roots themselves.
Carefully remove the plant from its pot and check the appearance of the roots. A healthy root system would look white.
If the roots are already turning brown to black and are very squishy and slimy when touched, then, it’s rotting. The roots will also smell awful.
Remember that the signs will vary depending on how severe the root rot is.
Sometimes, the signs are subtle especially if it’s just at the onset. As the rotting advances, you’ll see more of the signs described above.
Molds tend to grow in constantly wet soil. An overwatered Zz plant would have this condition.
If you see molds growing on the surface of the soil, it’s a sign that you cannot neglect.
You must check how the roots are doing down there. Most often than not, there are rotting portions hiding under the soil.
How to Treat Zz Plant Root Rot
Root rot can easily kill your Zz plant especially if you leave it untreated. Remember that the roots play an important role in channeling water and essential nutrients to the upper portion of the plant.
It will be difficult to know the exact damage of the root rot unless you pull the plant out of its pot.
Only then will you get a fair view of the rotten portion and how severe it is. To prevent the damage from spreading, it’s better to repot the plant.
Here is the step by step procedure on how to properly do it:
Water the plant thoroughly so the roots and soil will loosen.
Pour water into the pot and leave it for a few hours. This will ease the process of removing the Zz plant from the pot especially if it’s already pot bound.
Carefully remove the root ball from the pot.
Remember to be extra careful in this process. Some plants have already developed rotting stems at the base making it more vulnerable. Carefully remove the soil surrounding the roots.
Examine the roots and look for the rotten portions.
These rotten portions are brown to black in color and are slimy. They do smell awful too. Spot for these parts of the roots and see how far the damage is.
Trim the rotten roots.
Obviously, the rotten portions of the plant will no longer serve their function. That’s why you have to trim it down. Do this by carefully cutting the roots at least an inch right after the damaged area.
Make sure to use disinfected scissors to avoid the potential spread of diseases. Be careful not to mix diseased roots with other plants. Discard it properly.
Treat the roots with fungicide.
Fungicides will prevent the roots from pathogens. Use the appropriate fungicide for Zz plants and follow instructions while applying.
There are fungicides that are specific to a pathogen so you have to properly identify which of them is needed by your plant.
I found this Liquid Copper Fungicide (Check the latest price on Amazon) to work best against fungal diseases.
Prepare a clean and sterilized potting mix.
You can buy this from gardening stores for ready use. Moist the potting mix by watering it a few hours before you do the repotting.
Repot to a new and clean container.
If your Zz plant is suffering root rot caused by the fungus, don’t use the old pot and soil for repotting.
It will just transfer the diseases back. Instead, use a new and clean pot using fresh potting mix.
Using Appropriate Soil Mix
The right combination of particles in the soil mix improves its structure. A good soil structure has enough pore spaces where air could fill when it’s dry. When you water the soil, those air spaces will be filled with water.
To improve the soil structure of your potting mix, add peat moss or bark on the mixture.
This will make the soil porous. If you’re unsure of creating your own mixture, it would be better to buy premixed potting soil.
It’s important that you test the draining capacity of the soil before potting your plant. Pour water into the pot and see how fast it flows out of the holes.
If it takes more minutes, then, it’s not well-draining and you have to enhance the soil mix.
Watering After Repot
Plants experience shock after transplant or repotting. That’s why you have to take extra care of your Zz plant. To reduce the stress, you have to properly water the plant.
Thoroughly water the soil after repotting ensuring that it is saturated. Leave it for a few hours to drain, then, place it in an area where there’s part shade.
Check the soil to assess moisture level. Once it dries, you may water the pot again. Make sure to do deep watering.
Care After Repotting
Repotting is already a stressful process for plants so you have to give them extra care after that. One of which is to water the pot thoroughly after repotting.
The roots of the Zz are still in the process of getting acclimatized to its new environment. Naturally, it will have a hard time channeling nutrients and water to the stems and leaves. Providing water will reduce stress.
Also, make sure to put the Zz plant under a shaded place right after repotting to prevent excessive moisture loss. You should transfer it to brighter light little by little to avoid shocking the plant.
If the root rot of your Zz plant is getting severe, the only way to salvage it is to propagate the remaining healthy leaves or stems. After that, you can let go of the rest of the plant.
Here’s how to propagate a Zz plant using leaf and stem cuttings:
- Remove whole and healthy leaves from the unaffected stem of the Zz plant. Choose the leaves that have no hint of damage. It must be deep green in color and is already mature.
- Set it aside for a few hours giving it time to callous over.
- Prepare a well-draining, moist potting mix in a container. Insert the base of the leaf to the potting mix in such a way that it is facing upside down.
- Water the leaves gently and place them in a location where there is bright, indirect light.
- Wait for the leaves to develop small rhizomes at its bottom. It will take a month or so.
- Cut a healthy stem from the Zz plant using clean scissors. Also, choose the one that is already mature but not aged.
- Prepare a clear glass container and fill it in with water that’s about half.
- Place the cut stem to the container allowing at least half of the stem to soak. Put in a location where there’s enough light.
- Change water every 3 to 4 weeks or depending on how dirty the water gets. Watch out so that molds won’t develop.
- Wait for the rhizomes to grow at the bottom. Then, repot to a new container using a fresh potting mix.
- Water the Zz plant and place it under bright, indirect light.
Alternatively, you may plant the cut stem directly into the potting mix. Water it and place it in a partly shaded place. The stems will develop roots in a month or so.
You May Also Enjoy: Do ZZ Plants Need Fertilizer? (Tips and Common Mistakes)
Causes of Zz Plant Root Rot
There are many factors that can lead to root rot but most of them are a result of malpractice.
The good thing though is that it can be corrected. All you need is to be quick to observe the signs, diagnose properly, and take corrective measures.
The most prevalent reason why plants suffer from root rot is overwatering.
This is true especially for potted plants because they have limited space and water can easily get intact inside.
When it happens, the roots are stuck in stagnant water as if it’s been flooded.
The oxygen supply becomes limited affecting the Zz plant’s ability to respire.
Thus, the roots slowly die of suffocation. Dead plant parts will eventually decay in time.
How to Fix:
There is one thing you have to remember when watering a ZZ plant. It has big, fleshy rhizomes below the soil which serves as its water storage. Therefore, it doesn’t need much watering.
To avoid overwatering, here are some techniques you could follow to prevent your Zz plant from getting root rot. ( Source: University of Connecticut)
Always check the soil to assess its moisture needs.
Some of us may have developed the habit of watering our plants daily but it should not be the case for the Zz plant.
Regular watering won’t be needed if the plant has enough water in-store in its rhizomes. Instead of adhering to a schedule, make it a habit to check the soil first before deciding whether to water or not.
Let the soil dry before watering
ZZ plants would rather prefer a dry condition than a moist one. So, if you’re unsure whether to water the plant or not, better choose to skip the watering schedule.
To check if the soil is dry enough, stick your fingers an inch below. If it feels dry, then it’s time to water your plant. If it feels moist, then there is no need to add water at the moment.
Water the soil deeply.
To avoid developing a shallow root system, do deep watering. Remember that roots will move towards the source of water so if you water deeply, the roots will also go deeper into the soil.
What you can do is allow water to thoroughly wet the soil inside the pot. Let it saturate the medium so that all the roots have access to it.
Do not forget to drain excess water.
This is a very crucial practice when watering plants. You should always check if the excess water is going out of the drainage holes. That way, no stagnant water will remain in the pot.
Don’t forget to drain water from the pot coasters too. Coasters can hold water leaving the bottom part of the pot submerged in a pool of water.
Adjust watering frequency as needed.
More frequent watering is needed if the temperature is high or when humidity is lower. The same goes for when sunlight is much intense just like during summer.
This is because transpiration rates during these times are relatively higher. In contrast, low temperature, high humidity, and cold seasons won’t require frequent watering. ZZ plant doesn’t lose that much water. If you continue watering your plant, it will end up developing root rot.
Poor or Lack of Drainage
Even when you’re watering your Zz plant with enough water, if it lacks good drainage, it still is susceptible to root rot.
Water can still get stuck in the pot because they have no way out. If the holes are extremely small for the pot size, draining will not be as efficient.
Poor drainage leads water to stay in the container longer than necessary. It creates a waterlogging condition the same as that of overwatering.
How to Fix:
If your Zz plant is potted in a container where drainage holes are absent or insufficient, it’s time that you start making holes. Remove your Zz plant from its pot and drill new holes at the bottom. Test how fast the water seeps out of the holes.
If water easily moves out within a minute, then you’ve made good drainage.
Test this again once you’ve placed back the Zz plant in its pot. Make sure to remove any form of blockage.
Poor Drainage Capacity of Soil
The physical characteristics of the soil you use on your Zz plant also affect its draining capacity.
If the soil is compact, the rate of water infiltration is very low. As a result, there is this tendency that water will remain in the pot for longer periods.
A poorly drained soil has more clay in its composition. The lack of large pore spaces is the reason why water won’t flow freely into the soil. A poorly draining soil often feels sticky when touched.
How to Fix:
Improve the soil structure of your potting mix by adding peat moss, bark, or other organic materials. These particles improve the texture and structure of the soil by creating more pore spaces in between.
You can test whether the potting mix is well-draining by pouring water and observing how fast the liquid seeps out of the soil mix.
Another cause of root rot in potted plants is pathogenic infection. There are different types of bacteria and viruses that are present in the soil which leads to diseases in Zz plants. The most common pathogens are Phytophthora and Pythium.
These pathogens thrive in wet soil conditions. If the soil you used in potting is previously inhabited by these organisms, there’s a high chance that it will resurface. Once the roots are infected, the disease easily spreads out.
How to Fix:
To manage the infection, you can apply an appropriate fungicide on the soil as drenches. Isolate the plant away from other ornamentals to avoid spreading the disease. Remove infected portions immediately.
Lower the humidity level around the plant and the soil. This will prevent the organisms from thriving.
Inappropriate Size of Pots
Believe it or not, the size of the pot you’re using on Zz plants affects its overall health. Extra-large or extra small pots cause overwatering. Here is how it happens.
If the pot is too large, the tendency is for you to water more in order to saturate the soil.
On the other hand, If it is too small for the plant’s size, you’ll be tempted to water more often even if it’s not needed.
Either way, you’ll have the tendency to water excessively. Of course, everything in excess remains in the pot leaving the soil constantly wet.
How to Fix:
Make sure to get an idea of the size of your Zz plant. Now, you will be able to see if the size of the plant is proportional to its pot. Small plants need small pots and big ones need big pots.
Repot your Zz plant in a size-appropriate container so that the soil you put in is just enough for the plant.
I have mentioned earlier that temperature is a factor to consider when watering.
During times of low temperature, the moisture loss in plants is slow. This means that water will stay longer in their system.
If you consistently water your plants even when the temperature is low, there will be waterlogging in the soil. It then leads to root rot.
Another reason is that low temperature offers a favorable environment for pathogens to grow.
Once this happens, your Zz plant is in danger of getting infected by a disease specifically those that attack the roots.
How to Fix:
Lessen the frequency of watering during cold seasons. Make sure that the soil is dry before you water.
Expose your Zz plant under a generous amount of sunlight or artificial light to hasten evapotranspiration.
Watering During the Dormant Period
Dormancy in plants is a period where metabolic processes such as photosynthesis and respiration slow down.
This is commonly referred to as the period of rest because the plant ceases growing.
The slowing down in these processes leads the plant to utilize small amounts of water.
Watering during dormant periods would only result in excess water in the pot. It then remains stagnant for extended periods leaving the roots in a flooded condition.
How to Fix:
Withdraw water application during the dormant period. This happens during winter.
When the temperature starts dropping, lessen the amount and frequency of watering.
In most cases, your Zz plant will survive when even without water the entire winter season. If it starts wilting, then you may water it again.
How to Prevent and Control Zz Plant Root Rot
Root rot on Zz plants can certainly be prevented. You just have to learn how to employ the best practices when taking care of this plant. Here are the most important tips to follow:
You can prevent waterlogging by making sure that any excess water drains out of the pot.
By choosing the right size of the pot, ensuring enough drainage holes, and watering early in the morning, the chance of having stagnant water will be reduced.
To give enough time for water to evaporate out of the soil, water the Zz plant in the morning.
If you have missed your early morning routine, don’t try to compensate by watering the plant in the evening. It will make the plant susceptible to root rot.
Watering at night will only prolong the period by which moisture will stay in the pot.
The lower temperature at night will result in a slower transpiration rate. Pathogens love this kind of the environment too.
I have written another article on how often to water ZZ plant considering all the details you need to know about watering ZZ plant.
Appropriate Soil Mix
A well-draining soil is always a must for potted plants. Save yourself from future trouble by using the right kind of mix for your Zz plant.
Invest in using sterilized soil to avoid pathogens from infecting the roots of your plant.
Amend your soil with organic matter such as peat moss and bark to improve its structure.
Choose the Right Pot
The right size should always be in proportion to the size of your Zz plant. Avoid using too large or too small pots.
Whether you’re using terra cotta, ceramic or plastic pots, better opt for the ones with existing drainage holes.
Apply Fungicide as a Preventive Measure
It’s better to apply fungicide to the soil at the onset of transplanting to roll out the pathogen problem.
Remember that diseases inflicted by these organisms can be hard to control once it starts infecting the plant.
Provide Enough Light
Although Zz plants are tolerant of low light levels, it would be best to place them under bright, indirect light.
Light helps hasten the evaporation and transpiration process which can work to the advantage of your Zz.
There are different ways to save a Zz plant from root rot. Each depends on what causes the problem.
It’s important that you familiarize yourself with diagnosing the signs of root rot in plants before the damage worsens.
The signs mentioned above are those that occur commonly. However, there can be times where only one sign is present. That’s why you have to check the roots themselves to be sure.
While root rot may seem hard to deal with, remember that there’s always hope for your beloved Zz. After all, this plant is quite tough and hardy.