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Marimo Propagation

Updated on September 17, 2013
seh1101 profile image

Sean has been in the industry of gardening and landscaping since 2006. He is also a Certified Arborist that tends to focus on plant health.

Large (left) and small (right) marimo balls
Large (left) and small (right) marimo balls | Source

Marimo Propagation Overview

Marimo (Cladophora aegagropila) is actually a variety of fresh water algae that is common in the northern hemisphere. The spherical shape occurs in nature by water currents that cause the marimo to tumble on lake beds. The tumbling retains the spherical shape of marimo. "Marimo" is a Japanese word that literally means “ball seaweed.” Marimo is native to Japan, Iceland, Scotland, and Estonia. Marimo has been a protected species in Japan since as early as 1920. An annual three day marimo festival is held in Japan to pay tribute to marimo. It is also classified as a protected species in Iceland.

Marimo can be grown indoors and propagated to create smaller marimo. Propagation is very easy and rewarding. Dividing marimo is the best method of propagation. Retaining the spherical shape is accomplished differently compared to nature's process of tumbling marimo on the bottom of lake beds. Thread is used to tie the division into a ball to ensure a spherical shape as it grows.

It has been said that Marimo bring good luck and ever-lasting love to friends and loved ones.

Materials Needed

  • Marimo
  • Scissors
  • Thread
  • Container for Marimos (Jar, Glass, Fish Tank, etc)
  • Water

A small division removed from a parent marimo.
A small division removed from a parent marimo. | Source

Locations of Native Marimo

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A markerJapan -
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The marimo has been a protected species in Japan since as early as 1920.

B markerIceland -
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Marimo was given a status of "protected species" in Iceland in 2006.

C markerScotland -
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Marimo is native to the waters of Scotland.

D markerEstonia -
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Marimo can be found in and around Estonia.

Marimo Divisions

Dividing marimo is simple to accomplish. The picture on the right shows marimo that is about an inch and a half wide, which is large enough to perform a division. The marimo in the picture had a small division performed to preserve the size of the parent marimo. Although, the parent marimo is large enough to divide in quarters, thus creating four smaller marimo out of one parent marimo.

Following a few easy steps is all that is required to divide marimo.

  1. Select marimo with decent size to be divided.
  2. Decide how to divide the marimo (halves, thirds, quarters, etc).
  3. Gently squeeze the marimo to drain excess water. This makes it easier to cut with scissors.
  4. Use a sharp pair of scissors to cut the marimo into desired divisions. Marimo consists of many small filaments of algae bundled together, so cutting them apart will not harm the overall health of the marimo ball.
  5. Form the fresh divisions into a ball by rolling between the hands.
  6. Use a piece of thread to wrap around the new divisions and tie the ends together. This will retain the spherical shape of marimo.
  7. Place the new divisions into a container full of water. Do not used distilled water, because distilled water lacks vital minerals. Marimo needs minerals that are available in tap water. Chlorine-free tap water is preferred. Leave a container of tap water sit overnight to allow chlorine to dissipate.

Marimo grows very slowly (around 5mm per year), so do not worry if the divisions appear to lie dormant. The tiny filaments of algae will eventually grow thick enough to cover the thread used to retain the spherical shape as well.

Marimo Care

Water Requirements
Marimo is very easy to care for. It does not need aeration or filtration, but the water must be changed regularly to keep marimo healthy. Water changes should occur weekly. Rinse marimo with water to remove debris and buildup. When rinsing, give marimo a gentle squeeze, like wringing out a sponge. This helps remove buildup and debris as well.

Light Requirements
Marimo has adapted to low-light conditions due to their native residence on the bottom of lakes. Too much sunlight will cause discoloration, so placing in indirect sunlight is ideal. Artificial lighting, such as household light bulbs, is sufficient and will greatly reduce the chance of burning caused by strong sunlight.

Marimo Cautions

Growing marimo in a fish tank may cause a few minor problems to arise. Tanks with pump filters can become clogged around the intake and filter due to marimo filaments being sucked into the filter. Buildup will reduce the effectiveness of the filter, and the filter and pump will require cleaning.

Marimo may also be a target for some fish. Goldfish and bottom dwellers that scavenge will nip and slowly pick apart marimo. This will also increase the amount of filaments being sucked into the filter, as well as reduce marimo size. The loose filaments can also add to algae growth in the tank. The glass and tank may need to be cleaned more regularly if algae begins to flourish.


Marimo Poll

Do you own marimo?

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    • profile image

      Angel 3 years ago

      You can buy the moss balls AKA round Marimo algae on eBay at a very reasonable price I purchased one 2 years ago and mine is very Large now I am purchasing 6 more on eBay today I love mine very unique item.

    • seh1101 profile image

      Sean Hemmer 5 years ago from Wisconsin, USA

      renee rompies - That is amazing. Must have taken many years to reach that size. I have a misshapen marimo that is starting to flatten and I'm thinking about doing the same.

    • profile image

      renee rompies 5 years ago

      I have our two the size of grapefruits also put some on rock and it grew a across like a carpet

    • seh1101 profile image

      Sean Hemmer 5 years ago from Wisconsin, USA

      theraggededge - Haha, I have no idea. Its similar to seaweed, so maybe? I think the texture would be really off...kind of like chewing a wet cotton ball.

    • theraggededge profile image

      Bev 5 years ago from Wales

      Never heard of it. Looks really interesting. Is it edible (not that I want to eat it!)?

    • seh1101 profile image

      Sean Hemmer 5 years ago from Wisconsin, USA

      Janis - I found out about marimo while searching for aquarium plants. I decided to buy 3 marimo balls and I'm glad I did. I have 6 now via divisions, but the newly divided ones are still pretty small.

      c1234rystal - Marimo algae itself is common to the northern hemisphere, but the conditions to produce marimo balls are unique to a few countries. Water currents play a vital role in causing the algae to bundle together.

      GoodLady - You may be able to find marimo in pet shops over there. I had to order online, since all the shops in my area had no idea what I was talking about. Marimo ships well due to their low requirements. As long as they are moist, they will survive. Avoid "nano marimo" though. They are very small and not worth the price.

    • Johnathan L Groom profile image

      Johnathan L Groom 5 years ago from Bristol, CT

      detailed and catagorized work here...

    • GoodLady profile image

      Penelope Hart 5 years ago from Rome, Italy

      I want one marimo - it is the most interesting Hub. I think marimo would make my 2 year old happy in her room, but where could I find it in Italy?

    • c1234rystal profile image

      c1234rystal 5 years ago

      Interesting hub; just one question. How is Marimo native to places as far from each other as Japan and Estonia? It must have migrated from one place to the other. Do you know where exactly it originated? :)

    • Janis Goad profile image

      Janis Goad 5 years ago

      Interesting hub, SEH110. I never heard of Marimo before. How did you run across them?