How to Dye Fabric with Shredded Mimosa Hostilis Root Bark
To dye fabric with shredded Mimosa hostilis root bark, weigh the dry fabric, scour it, mordant it, then simmer it gently in a strained bark bath. Use 50 g of bark per 100 g of fabric for a light shade and up to 100 g for a deep one. The full method, with amounts for each step, is below.
What you need
- Shredded Mimosa hostilis root bark: 50 to 100% of the dry fabric weight
- Natural-fibre fabric or yarn: wool, silk, cotton or linen
- A mordant: alum for wool and silk, tannin plus aluminium for cotton and linen
- A stainless steel or enamel pot kept only for dyeing, a strainer and a piece of fine cloth
- Kitchen scales, gloves, a long spoon and a thermometer if you have one
Only natural fibres take up plant dyes. Polyester and other synthetics stay pale, and blends dye unevenly because only the natural part of the yarn absorbs colour.
How much bark to use
Natural dyers measure everything against the dry weight of the material, called weight of fibre (WOF). Weigh the fabric before it gets wet, then multiply.
| Shade | Bark (% of fabric weight) | For a 150 g T-shirt | For 500 g of yarn |
|---|---|---|---|
| Light: soft pink to mauve | 50% | 75 g | 250 g |
| Medium: clear purple-brown | 75% | about 115 g | 375 g |
| Deep: plum to brown | 100% | 150 g | 500 g |
These are starting points. Bark varies from batch to batch and every fibre behaves differently, so dye a small sample first. The dye calculator does the sum for any weight in grams, ounces or pounds.
Step 1: scour the fabric
Scouring removes the oils, wax and factory finishes that stop dye reaching the fibre. It is the step beginners skip most often, and the usual cause of patchy colour.
- Cotton and linen: simmer for about an hour in water with soda ash (about 5% of the fabric weight) and a little pH-neutral detergent (about 2%), then rinse well.
- Wool and silk: wash gently in warm water with a mild, pH-neutral detergent. Avoid sudden temperature changes and rough handling, which felt wool.
Step 2: mordant
A mordant bonds to the fibre and gives the dye something to hold on to. The bark contains tannin and will colour unmordanted fabric, but the shade is paler and fades faster.
- Wool and silk: alum at 10 to 15% of the fabric weight. Dissolve it in hot water, add it to a pot of warm water, add the wet fabric and hold at a gentle simmer for about an hour. Let it cool in the pot.
- Cotton and linen: alum alone does not bond well to plant fibres. Soak the fabric in a tannin bath first, then in an alum or aluminium acetate bath, following the amounts your mordant supplier gives.
Step 3: make the dye bath
- Put the shredded bark in the pot and cover it with water. Allow about 3 litres for every 100 g of fabric so the cloth can move freely later.
- Heat slowly to a gentle simmer and hold it just below boiling for about an hour. A hard boil is not needed and can dull the colour.
- Let it cool, then strain the liquid through fine cloth into a clean pot. Shredded bark strains out easily, which is its main advantage over powder.
For more colour from the same bark, simmer the strained shreds a second time in fresh water and add that liquid to the first.
Step 4: dye the fabric
- Add the damp, mordanted fabric to the strained bath. It should be fully covered.
- Heat gently for about an hour. Keep wool and silk below a simmer and bring the heat up slowly.
- Move the fabric every few minutes. Folds that sit still against the pot dye darker and cause streaks.
- Turn off the heat and leave the fabric in the bath until cool. Leaving it overnight gives a deeper shade.
Step 5: rinse and dry
Rinse in cool water until it runs nearly clear, then wash gently with a mild detergent and dry out of direct sun. Colour usually looks a shade lighter once the fabric is dry.
Changing the colour
- Grey and charcoal: dip the dyed fabric briefly in a separate bath with iron (ferrous sulphate) at 1 to 2% of the fabric weight. The shift happens within minutes, so watch closely and rinse well.
- Paler second batch: the used bath still holds colour. A second piece of fabric dyed in it comes out lighter. Dyers call this an exhaust bath.
- Deeper shade: dye the same piece twice, letting it dry in between, or move up to 100% bark.
If something goes wrong
| Problem | Likely cause | What to do |
|---|---|---|
| Patchy or streaky colour | Fabric not scoured, pot too small, or fabric left still | Scour again next time, use more water and stir more often |
| Colour too pale | Too little bark, no mordant, or a short soak | Use more bark, mordant first and leave overnight |
| Colour washes out | Mordant step skipped or rushed | Re-mordant and dye again |
| Dull, greyish shade | Iron in the water or in the pot | Use a stainless or enamel pot and filtered water |
Looking after dyed fabric
Wash naturally dyed fabric separately for the first few washes, in cool water with a mild detergent, and dry it in the shade. All plant dyes soften slowly with light and washing; careful mordanting is what slows that down.
Safety
Keep your dye pot and tools for dyeing only and never use them for food. Wear gloves, protect worktops, and store mordants in labelled containers away from children and pets. Our guide to handling the bark safely covers dust and stain prevention.
Common questions
Can I use powder instead of shredded bark?
Yes. Powder releases colour faster, and the weights are the same. It is harder to strain, so pour the bath through a tightly woven cloth or a coffee filter before adding fabric.
Do I have to mordant?
For anything you plan to wash or wear, yes. Unmordanted fabric takes some colour from the tannin in the bark, but it fades much faster.
How much fabric does a 500 g pack dye?
About 500 g of fabric at a deep shade, around 665 g at a medium shade and 1 kg at a light shade.
Can I dye with it in a bucket without heat?
Heat gives stronger, more even colour. A long cold soak of a day or more in a strained bath will still colour mordanted fabric, but more softly.
For quantities for any project, including soap and wood, see the project planner. Short answers to other questions are on the FAQ page.
Sources
- The Maiwa Guide to Natural Dyes: weight of fibre, water and mordanting.
- George Weil, a practical guide to natural dyeing: dyestuff quantities for barks.
- Elka Textiles, preparing plant fibres: scouring cotton and linen.
- Apple Oak Fibre Works, mordants: alum rates and why alum alone does not suit plant fibres.
