Karamushi grows back no matter how many times it is cut. It spreads almost unnoticed around fields, along woodland edges, and beside old houses. It is sometimes treated as a troublesome weed, but the karamushi fiber obtained from its stems has long been used to make yarn and cloth.
Karamushi (Boehmeria nivea / ramie) is known as a plant that yields strong bast fiber.
▼ Wild karamushi. Even after cutting, it grows back vigorously.
From Hand-Splicing Karamushi Fiber to Spinning It into Yarn
At Hitotsuya（ひとつ屋）, we are now experimenting with this wild-growing karamushi, hoping to turn it first into yarn and, someday, into cloth.
Our aim is not to reproduce traditional jōfu-making exactly as it was done in the past. Instead of the hand-splicing method used for jōfu and similar textiles—splitting fibers finely and joining them into one continuous yarn—we are asking whether these fibers can be spun.
In an earlier post, “Karamushi Weaving ②”, we also extracted fiber from karamushi and tried to take it on toward yarn and cloth. This time, however, we are looking for a less labor-intensive way to obtain fiber suited to spinning.
- What stage of growth is best for harvesting karamushi?
- Is it better to remove the bark before processing?
- Can the stems be processed whole, without peeling off the bark?
There is still so much we do not know. That is why we will change the conditions and test them one by one.
Water Retting Karamushi Fiber under Three Different Conditions
For this experiment, we began water retting under three different conditions.
Retting is a process that uses water, microorganisms, and related action to loosen the tissues around bast fibers, making the fibers easier to separate from plant stems. It is also used in processing fiber plants such as flax.
- Dried karamushi bark — to see how the outer bark and gummy substances change when dried material is returned to water.
- Fresh, undried karamushi bark — to see how much the outer bark loosens while the material still retains its fresh softness.
- Karamushi dried as whole stems without peeling — to test whether retting the stems whole can work.
Since around 5:00 p.m. on August 12, 2026, each sample has been soaking in water while we observe how its condition changes.
▼ From front to back, we compare three conditions: dried bark, fresh undried bark, and dried whole stems with the bark left on.
Could Younger Karamushi Produce Fiber That Is Easier to Spin?
One point that has stood out in our trials so far is the maturity of the stems. Karamushi that has grown too mature can develop tough outer bark that sometimes remains stubbornly attached even after soaking, drying, beating, and brushing.
Younger karamushi, on the other hand, may still have softer outer bark and could be easier to handle as fiber for spinning.
Our purpose is different from traditional jōfu-making. Hitotsuya is looking for fiber that is as soft, pale, and “easy to spin” as possible. From that perspective, harvesting while the plants are still young may suit our goal better than letting them grow to full size.
Turning a “Troublesome Weed” into a Renewable Fiber Resource
If young karamushi can be used, another interesting possibility appears: harvesting it several times in a single year.
In an area we cut recently, some plants had already regrown to about 30 cm. If young karamushi around 50–60 cm tall can be harvested repeatedly, the “troublesome weed that keeps growing back no matter how often it is cut” might, from another point of view, become a fiber resource we can use year after year.
Of course, we also need to find out how well the plants can recover when they are cut repeatedly.
- How many times can it be harvested in one year?
- How should the plants be helped to recover after cutting?
- Can they be managed with materials that circulate within Hitotsuya, such as compost, grass mulch, and ash from the kamado hearth?
In other words, once we begin researching yarn-making, it naturally leads us into researching how the plants themselves should be grown.
Retting Is Still Only a Pretreatment
In this water-retting trial, we will compare roughly 24, 36, and 48 hours, looking at how the outer bark lifts, changes in color and sliminess, and how much the fibers weaken.
We do not expect retting alone to produce finished fiber. First, water retting loosens the outer bark and gummy substances; then we dry, beat, and dry-brush or comb the material. If necessary, we will also test a mild wood-ash lye treatment, washing, and bleaching.
By combining these steps, we hope to bring the fiber gradually closer to a “spinnable state” and compare the differences.
We do not have the answer yet. But each time we work with our hands, a little more becomes visible.
Karamushi is a fiber plant that has been used for generations. But Hitotsuya does not want simply to retrace old methods. We want to turn wild karamushi fiber into yarn in a way that is possible for Hitotsuya today—and someday, into cloth.
Another experiment toward that goal has now begun.