ZZ plants grow from rhizomes which look like small potatoes underground. It is ideal to plant ZZ plant rhizomes 1-2 inches below the surface of the soil. If you expose the rhizomes they can dry out too fast and wrinkle. Over time as the plant grows bigger or fills out the pot you may notice the rhizome poke up through the soil.
This is a good sign that it is time to repot your ZZ plant. Tip the whole plant out of the pot and separate the rhizomes to make multiple plants or plant them in a bigger pot.
What can happen if you expose ZZ rhizomes
ZZ rhizomes help the plant to hold water. This makes them incredibly drought tolerant and will happily last for at least 4 weeks without water. If you expose the rhizomes they can dry out and they will not hold water for as long. They won’t have the insulation from the soil which helps to keep the soil and the plant moist for longer
If more than around half of the rhizome is sticking above the soil it can dry out and it can slow the plant’s growth. It is best to plant ZZ plant rhizomes 1-2 inches below the soil surface. This means that it can absorb and hold water more effectively.
How to plant ZZ rhizomes
The best way to plant ZZ rhizomes is to tip them out of their original pot and shake off the soil from around the rhizomes. This will expose all of the rhizomes and show you how many plants you have. You can gently separate the rhizomes where they will naturally come apart.
You can have as many plants as there are rhizomes but it is best to let them separate where they are already apart or only gently attacked. If you cut the rhizome it could allow diseases to enter the plant.
If there are large rhizomes joined together you can gently separate them by snapping them apart. A small break will not be a problem.
Do ZZ plants like crowded roots?
ZZ plants that will actually grow well in a tight pot. You can fit more than 10 rhizomes even in a small 5 inch pot. Eventually the ZZ plant will fill the pot and it will feel firm. To keep the ZZ plant growing fast it is best to repot them every 2-3 years to give them more space and fresh soil.
If you see lots of roots coming out the bottom of the pot it is time to snip them off and repot the plant. The rhizomes will be large and ready to separate if you want more plants. You can also plan the whole thing in a new larger pot. Choose a pot that is 2 inches wider or deeper to give the plant more room to grow.
Can a ZZ plant grow from a rhizome
ZZ plants can grow from a single rhizome but it will depend on how large and healthy the rhizome is. You should always try to transplant rhizomes that have stems and leaves so the plant can continue to photosynthesize. It is ideal if the rhizome has at least 3 stems so that it can recover quickly.
If the rhizome ends up without stems, you can plant it out but it won’t always grow well. Make sure you plant it with the roots facing down and the stems pointing upwards. Look out for the areas that the old stems were growing so that you know which way is up.
Why ZZ plant tubers become exposed
ZZ plant tubers can become exposed over time as the plant grows. As the soil level drops over time and the rhizomes grow larger they can pop through the surface of the soil. The larger the plant the more likely the tubers are to rise to the surface.
Over time potting soil will naturally drop in level. As the organic matter in the soil breaks down, it will leave the sand and larger particles. This will drop down, expose the top of the rhizomes. The plant can still grow well but it is best to repot them after 2-3 years. This will protect the rhizome and allow the plant to grow quickly and store water well.
Why you should avoid burying the rhizome too deep
Burying the rhizome too deep in the soil can cause the rhizome to rot. The deeper parts of the potting soil can stay wet for longer and the rhizome can rot. It will turn a dark color will go soft. This is a sign that the rhizome is buried too deep and is becoming damaged.
It is best to repot the rhizome if the stems are showing signs of damage. Repot the plant if the rhizome is below 3 inches deep, the stems are turning black, leaves are turning yellow or brown leaf tips.
Exposing ZZ rhizomes | Summary
ZZ rhizomes can become exposed over time as the soil level drops and the plant grows larger. It is ideal not to do this deliberately but to plant the rhizome 1-2 inches below the soil. This will protect the rhizome but to prevent it from rotting. If more than half of the rhizome is popping through the soil it is time to repot to protect the plant. It should grow back quickly and can send up new stems within 1-2 weeks in spring.