Wabi-kusa: The Japanese Ball of Marsh Plants

Wabi-kusa is a tiny green world in a glass bowl: a ball of nutrient-rich substrate densely planted with marsh plants sits in shallow water and gradually turns into a lush little mound. It comes from Japanese aquascaping and is now popular as an unusual decoration for a desk or windowsill.

Greenery for your home: potted plants.

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What wabi-kusa is

The name combines the Japanese idea of wabi, the beauty of simplicity and naturalness, with kusa, meaning grass. The idea is to grow a piece of riverbank meadow: plants that live underwater in an aquarium grow here in their emersed form, drawing moisture from the ball and the air. Later the ball can be placed in an aquarium and the plants will switch to their submerged form.

Which plants to use

• Rotala: fine stems with small leaves that turn red in good light.
• Ludwigia: green and reddish forms that grow fast.
• Hemianthus and other carpeting plants: they form a dense “lawn”.
• Hygrophila, alternanthera: for bigger accents.
• Aquatic mosses: for a natural look at the base.

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How to assemble a wabi-kusa

• Use a ready-made wabi-kusa ball or roll one from moist aquarium soil, binding it with fine thread if you like.
• With tweezers, plant small bunches starting at the top and working round the ball.
• Set the ball in a glass bowl and add water so it covers only the bottom of the ball.
• For the first weeks you can cover the bowl with a lid or perforated film to keep humidity high while the plants settle.

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Care

• Light. Bright: a light windowsill without scorching sun, or an LED grow light for 8–10 hours a day.
• Humidity. Mist with soft water once or twice a day, especially when the heating is on.
• Water. Change the water in the bowl weekly and keep the level low.
• Trimming. Trim overgrown stems with scissors so the ball keeps its shape.
• Feeding. Occasionally add a small dose of liquid aquarium plant fertiliser to the water.

If you enjoy Japanese ways with plants, try a kokedama or bonsai too.

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FAQ

Why are my wabi-kusa plants turning yellow?

Usually there is too little light or the air is too dry. Add a grow light and mist more often.

Can I move a wabi-kusa into an aquarium?

Yes. The plants will gradually swap their emersed leaves for submerged ones; this is normal adaptation.

Author: Maria Svitlovir

Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.

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