How To Get Rid Of ZZ Plant Black Spots On The Stem – & Valuable Prevention Tips

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Last Updated on January 20, 2023 by Urska

Looking to get rid of pesky ZZ plant black spots on the stem? Check out our easy-to-follow guide for tips and tricks to have your plant looking healthy again in no time!

What Are Black Spots On A ZZ Plant?

Zamioculcas zamiifolia,  commonly known as ZZ plants or Zanzibar gems are perennial plants native to Eastern Africa and parts of Southern Africa. They are flowering plants of the family  Araceae.

These plants are low-light plants and if given too much will develop black spots on stems. These spots are usually not deadly but are a stress response that can be remedied. As long as the black spots are dry and not wet and moldy, your plant can recover.

In addition to direct sunlight exposure, black spots on the stems of ZZ plants can be caused by fungal or bacterial diseases and insect infestations. These could happen after the plants have been allowed to get wet and remain in the water for a prolonged period.

Black spots can also occur on ZZ plant stems as a result of root rot. This is often caused by overwatering your plants, which can be detrimental to the health of your plant and even fatal.

Because there are a number of possible causes of black spots on your ZZ plants stems, you need to find out the exact cause before taking any treatment actions. 

zz plant brown spots on leaves

How Do You Fix ZZ Plant Black Spots On The Stem? – Possible Causes

When you notice the black spot on your ZZ plant stem, go through the possible causes listed above to determine what the cause of the spots on your plants could be, and then decide on the cause of action.

Cause 1: Too much light exposure

As we have already established that ZZ plants require low-light environments to thrive, if they develop black spots on their stems due to being exposed to too much light, you know it is a stress response. These spots are not deadly. Simply move your plant to a darker part of the house, room, or a shaded area and your plant will recover in no time.

Cause 2: Root rot

If you suspect that the spots could be caused by root or stem rot, stop watering your plants until the problem has been sorted out. If the black spots on your ZZ plant stem are at the base of the stem close to where the soil starts and the spots are slimy, this could be a sign of root rot.

Cause 3: Fungal infection

If it seems like your ZZ plant has a fungal infection such as from black mildew that is causing the black spots in the stem, you will need to apply a fungicide to the affected areas to stop the infection from spreading. There are various fungicides available in the markets. It would be best to use more organic ones such as neem oil. Neem oil is effective and poses less risk to your plants than chemical fungicides. However, whichever fungicide you decide to use, make sure you follow the directions on the pack for optimum results.


Cause 4: Poor ventilation

Like most plants, ZZ plants need environments with good air circulation to thrive. If your ZZ plant developed these black spots while it was in an area with poor ventilation, simply move it to a well ventilated area and observe if the spots disappear.

Cause 5: Excess moisture

Avoid misting your ZZ plants. These plants cannot tolerate excess water so do not give them any more water than is needed. This is because damp, humid conditions are the ideal breeding ground for fungi which will cause problems for your plants.

Cause 6: Problems with the soil

If you have tried all of the above remedies and your plants are not responding well, the problem might be in the pot or the soil in which your ZZ plant is grown. You will need to repot your plant. Check for damaged or infected roots when you repot your plants and remove them so that the black spot problem does not persist.

Prevention Tips For a ZZ Plant Black Spots On The Stem

To prevent further black spots from appearing on your ZZ plant stems, you can: 

  • limit sun exposure to your plant
  • limit the amount of moisture you expose or supply your ZZ plant with, to help limit fungal infections
  • do not put your plants in a tray with water as this may lead to issues such as root rot
  • remove damaged stems, snip these off half an inch above the soil level

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Final Thoughts

ZZ plants are some of the easiest plants to grow indoors due to their low maintenance requirements. Provide these plants with an ideal growing environment and they will thrive. This will also help prevent health problems such as those that cause black spots on the stems.

But do not despair if your plants are already showing signs of these, they can still be saved. Also remember that the black spots may never completely disappear as they could be sunburn. However your plants will be noticeably healthier and happier, and no more black spots will be developing.

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What do black spots on plant stems mean?

Black spots on plant stems could be a number of reasons ranging from too much light exposure, excessive watering, root rot, stem or fungal or bacterial infections.

Do ZZ plants turn black?

The ZZ plants may turn back on the stems if they completely rot and are about to die.

Read more about Why Is My Zz Plant Not Growing – 5 Slow Growth Fact Of The Zz Plant

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