Quick answer: buy powder for soap, cosmetics and the fastest dye baths, shredded bark for dye baths that are easy to strain, and whole bark if you want the longest storage life or prefer to cut and grind it yourself. All three are the same inner root bark of Mimosa tenuiflora; only the cut is different.
The three forms compared
| Whole | Shredded | Powder | |
|---|---|---|---|
| What it is | Uncut strips of inner root bark | Loose fibrous strands | Finely milled bark |
| Colour release | Slowest; soak overnight | Medium | Fastest |
| Straining | Very easy | Easy | Needs a fine cloth |
| Storage life | Longest | Good | Shortest; keep airtight |
| Best for | Long-term stock, grinding to order | Textile dyeing, leather work, infusions | Soap, cosmetics, quick dye baths |
Why the three forms behave differently
The chemistry is identical. A 2022 study measured 23.4% condensed tannins in the bark of this tree, and that does not change when the bark is cut or milled. What changes is surface area. Water can only reach the outside of a piece of bark, so the finer the cut, the faster the colour comes out. Powder has the most exposed surface and whole strips the least.
The same exposure works against you in storage. Air, light and moisture also act on the surface, which is why whole bark keeps its strength longest and powder should be kept airtight and used first.
Choose by project
| Project | Best form | Why |
|---|---|---|
| Dyeing cotton, linen, wool or silk | Shredded | Fast colour, strains out cleanly |
| Colouring vegetable-tanned leather | Shredded | Easy to remove from the bath |
| Infusing oil for soap or balm | Shredded | Leaves a clear, speck-free oil |
| Cold-process and melt-and-pour soap | Powder | Blends directly into the batter |
| Clay masks and sugar scrubs | Powder | Fine, even texture |
| Tannin wash for darkening wood | Powder | Makes a strong tea quickly |
| Long-term stock, or grinding to order | Whole | Longest storage life |
The project planner gives the quantity and a printable instruction sheet for each of these.
Dyeing fabric or yarn
Shredded bark is the usual choice. It gives up its colour in about an hour of gentle simmering and lifts out of the pot without leaving specks on the cloth. Our fabric dyeing guide walks through the full method.
Making soap or cosmetics
Powder blends straight into soap batter and cosmetic bases. If you want colour without speckle, infuse oil with shredded bark instead. See using root bark powder in soap making.
Leather tanning and colouring
Shredded or whole bark works well, because the pieces are simple to remove from a tanning liquor.
Buying in bulk or storing for a long time
Whole bark exposes the least surface to air and light, so it holds its colour strength longest. You can break off and grind what you need.
How much should you buy?
For dyeing, work from the dry weight of the fibre. A medium shade takes roughly half the fibre weight in bark, and a deep shade roughly the same weight as the fibre. The dye quantity calculator does the sum for you.
| Project | Approximate bark needed |
|---|---|
| One cotton T-shirt (about 150 g), medium shade | about 75 g |
| 1 kg of yarn, medium shade | about 500 g |
| 1 kg of yarn, deep shade | about 1 kg |
| Soap: 10 batches of 1 lb of oils each | about 10 teaspoons of powder |
Packs run from 500 g to 100 kg, and the price per kilogram falls as the pack size goes up.
Price per kilogram by pack size
Larger packs cost far less per kilogram. These are our prices in November 2026; check the product pages for current figures.
| Pack | Whole | Shredded | Powder |
|---|---|---|---|
| 500 g | $164.90 per kg | $168.38 per kg | $170.98 per kg |
| 1 kg | $140.12 | $143.07 | $145.29 |
| 3 kg | $126.13 | $128.78 | $130.78 |
| 5 kg | $113.52 | $115.91 | $117.71 |
| 10 kg | $102.17 | $104.32 | $105.94 |
| 20 kg | $71.52 | $73.03 | $74.16 |
| 50 kg | $50.06 | $51.12 | $51.91 |
| 100 kg | $35.04 | $35.78 | $36.34 |
Two things stand out. Whole bark is the cheapest form at every size, by a few percent, because it needs the least processing. And the jump from 10 kg to 20 kg is the biggest single drop, so a workshop that uses bark regularly saves most by buying at 20 kg or above. Orders over $200 also take 20% off with the code DEAL20.
How to judge quality
- Colour: the inner face of the bark should be a deep red-purple to purple-brown. Pale, greyish bark gives weaker colour.
- Plant part: look for inner root bark, not stem bark or mixed plant material.
- Cleanliness: no soil, stones, mould or musty smell.
- Powder: an even, fine grind with no added fillers.
For our own bark, lab results and a certificate of analysis (COA) can be provided on request.
Storage
Keep every form in an airtight container in a cool, dry place away from direct light. Moisture is the main risk, so reseal packs straight after use.
Common mistakes
- Buying powder for dyeing fabric. It works, but straining takes longer and stray particles can speck the cloth. Shredded is easier.
- Buying whole bark for soap. You will have to grind and sieve it first. Order powder unless you want to mill it yourself.
- Storing powder in an open bag. It takes up moisture quickly. Move it to an airtight jar.
- Assuming powder is stronger. It releases colour faster, but the same weight of any form contains the same material.
Can you mix forms?
Yes. Some dyers start a bath with shredded bark and add a spoonful of powder to deepen the colour quickly. Others keep whole bark in stock and grind small amounts as they need powder for soap. Since the material is the same, quantities by weight stay the same whichever form you use.
Frequently asked questions
Is powder stronger than shredded bark?
Weight for weight they contain the same material. Powder releases its colour faster because more surface is exposed, so a short dye bath can look stronger.
Can I turn whole bark into powder myself?
Yes. Break it into small pieces and grind it in a mill or blender kept for craft use. Wear a dust mask.
Is Mimosa tenuiflora the same as Mimosa hostilis?
Yes. Mimosa hostilis is an older botanical synonym for the same tree.
Sources
Mimosa Tenuiflora Root sells root bark as a raw material for dyeing, soap making and cosmetic crafting only. It is not sold for human consumption.