Rhubarb Root Natural Dye
Rheum palmatum · Cut or Ground · Collected in China
Rhubarb root is a wonderfully responsive natural dye, producing earthy yellows, yellow-browns and olive greens, as well as experimental pink and red brown shades under alkaline conditions.
The root contains tannins and anthraquinone-type colourants. Its final colour varies considerably according to the fibre, mordant, water chemistry, pH and modifiers used.
Choose from cut or ground rhubarb root.
At a glance
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Botanical name: Rheum palmatum
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Plant part: Root
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Country of collection: China
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Forms: Cut or ground
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Colours: Yellow, yellow-brown, olive green, pink and red brown
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Fibres: Wool, silk, cotton and linen
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Mordant: Recommended; use a fibre-appropriate method
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Colour response: Highly dependent on pH and mordants
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Yellow and green colourfastness: Generally good
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Pink and red colourfastness: Medium
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Origin: Botanical and suitable for vegan projects
Choosing a form
| Form | Suggested quantity | What to consider |
|---|---|---|
| Cut rhubarb root | Up to 100% WOF | Easy to strain and may be extracted more than once |
| Ground rhubarb root | Approximately 50% WOF | Releases colour readily but produces more sediment; use a fine dye bag |
Ground rhubarb has a greater surface area and generally releases its colour more readily than cut root.
How much to use
For a strong shade with cut rhubarb root, begin with:
100g cut rhubarb root per 100g dry fibre
Equivalent to 100% WOF - weight of dry fibre.
For a strong shade with ground rhubarb root, begin with:
50g ground rhubarb root per 100g dry fibre
Equivalent to 50% WOF.
For lighter shades, begin with approximately 25% WOF. These quantities are starting points only; sample first when working towards a particular colour.
Colour possibilities
| Method | Possible result |
|---|---|
| Approximately 25% WOF | Soft yellow to yellow-brown |
| Approximately 50% WOF | Deeper yellow-brown |
| Higher dye concentration | Stronger yellow and earthy brown shades |
| Careful iron modification | Olive, khaki, grey-green or deeper green-brown |
| Alkaline modification | Pink, coral or red brown, generally with poorer permanence |
Results vary according to the form of rhubarb, fibre, mordant, water chemistry, pH, temperature and processing time.
Basic guide for wool
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Prepare: Scour and mordant the wool with alum using your preferred wool-mordanting method, then wet it thoroughly.
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Soak: Cover the rhubarb root with water and leave it to soak overnight.
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Extract: Heat the soaked root and liquid gently for one to two hours.
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Strain: Strain the dye liquid through a fine cloth. Ground rhubarb is best contained in a dye bag to reduce sediment.
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Dye: Add the thoroughly wetted wool and heat gently for approximately one hour. Use enough water for the fibre to move freely.
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Deepen: Turn off the heat and leave the fibre in the cooling dye bath overnight if a deeper colour is required.
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Modify - optional: Remove a small sample or portion of the dye bath before experimenting with iron or soda ash. Add modifiers gradually and observe the colour closely.
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Finish: Rinse thoroughly, wash gently and dry away from strong, direct sunlight.
Protein and cellulose fibres require different preparation.
Dyeing cotton, linen or other cellulose fibres? Find suitable mordanting methods here.
Modifying with iron
Iron can shift rhubarb yellows and browns towards olive, khaki, grey-green and deeper green-brown shades.
Always dilute iron before adding it to the bath. Begin with a very small quantity -approximately 1-3% WOF - and increase only if necessary.
Iron continues to darken the colour, and excessive iron can make wool and other fibres harsh or brittle. Test a sample first and use only enough to create the desired shift.
Creating pinks and reds
Rhubarb root can shift towards pink, coral or red brown in an alkaline bath.
Dissolve a small amount of soda ash separately and add it gradually while monitoring both the colour and pH.
Strong or prolonged alkalinity can damage protein fibres such as wool and silk. For these fibres, modify a small sample first before making the full dye bath strongly alkaline.
Cellulose fibres tolerate alkalinity better, but the resulting pink and red shades are generally much less colourfast than rhubarb’s yellows and greens.
Tips from the dye pot
| Tip | Details |
|---|---|
| Contain ground root | Place ground rhubarb in a fine dye bag to reduce sediment. |
| Reuse cut root | Cut rhubarb may be extracted more than once for additional colour. |
| Use iron sparingly | A small quantity can shift the colour significantly; excessive iron can damage the fibre. |
| Raise pH carefully | Add dissolved soda ash gradually and avoid prolonged high alkalinity on wool or silk. |
| Test separately | Modify a small sample or portion of the bath before treating the entire project. |
| Keep notes | Record the fibre, mordant, dye form, WOF, pH, temperature, modifiers and processing time. |
Colourfastness
The yellow, yellow-brown and iron-modified green shades produced by rhubarb root generally have good colourfastness when the fibre is suitably prepared, mordanted, dyed and finished.
Pink and red shades created under alkaline conditions have poor colourfastness and may fade or change during washing, storage and exposure to light.
Colourfastness still depends on the fibre, mordant, modifier, depth of shade and aftercare. Sample and test when permanence is important.
Storage and safe handling
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Store tightly sealed in a cool, dry place away from direct sunlight.
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For textile dyeing and craft use only.
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Not for consumption or use in food, drinks, cosmetics or herbal preparations.
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Avoid creating or breathing dust, particularly when handling ground rhubarb root.
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Prevent contact with eyes, mouth and open wounds.
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Wear gloves and suitable protective equipment when handling dusty material.
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Follow the safety instructions for all mordants, iron, alkalis and other modifiers used.
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Add iron and soda ash carefully; excessive quantities can damage fibres.
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Use dedicated dyeing utensils and containers—never food-preparation equipment.
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Keep away from food and out of reach of children and pets.
For textile dyeing and craft use only - not for consumption.
What you receive
Your chosen net weight of cut or ground rhubarb root supplied in a pouch.
Please check the selected form and pack size carefully before ordering.
Mordants, iron, soda ash and other dyeing supplies are sold separately.
Packaging
We pack as sustainably as we can while protecting your dye materials. Pouch types may vary according to pack size and the availability of our preferred lower-impact options.
Display jars are not included.
Learn with us
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