Updated: Jun 28, 2021
Soapwort, which gets its name from its detergent and soapy properties, is a common garden and hedgerow plant. It is easy to grow, and has a captivating history which links it to the Turin shroud, medieval washing techniques, preservation of Tudor lace and Alpine sheep cleaning!
Although it makes a mild soap, it is effective in dissolving fat and grease, so can be used to clean hair and hands as well as being a gentle wash for delicate fabrics.
In this article, I’ll be looking at how to grow soapwort, how to prepare and use it as a soap, and some of its fascinating historical uses as a natural detergent.
If, like me, you are interested in natural gentle soap, and discovering the sustainable and traditional sources for household products, then read on…
[Photo: Author's garden soapwort jungle]
What is Soapwort and How Do I Make Soap From It?
Soapwort, or Saponaria officinalis, is a common flowering perennial in the carnation family which gets its name from its soapy and detergent properties. The leaves, stems and roots on a mature plant produce saponins, which form a natural soap. When prepared correctly, the plant material produces a cleansing lather.
Saponaria officinalis takes its name from ‘sapo’ the Latin for ‘soap’, to which is added the term ‘officinalis’, which is a Medieval identification indicating its other use as a medicinal herb. It is now native to Central and Southern Europe but is thought to have originated in the Middle East and have been introduced to England from northern Europe by Franciscan and Dominican monks.
It is a hardy perennial plant which can be invasive. The plant spreads via the rootstock and can be remarkably adept at occupying your garden, springing up between paving stones and at distances of many feet from the original plant. It can reach 3 feet tall and has long oval leaves and clusters of pink flowers. It flowers between July and September with a delicate fragrance which is most intense at night.
It has a long history of use - as a medicinal herb, as washerwoman’s soap, a fuller’s (cloth finishing worker) ingredient and as a common garden and wild flower. This is reflected in its many folk names which include: lady-by-the-gate, chimney pink, foam dock, bouncing bett, sweet betty, bruisewort, dog cloves, soap root, latherwort, fuller’s herb, fuller’s grass, foam dock, gill-run-by-the-street, crow soap, hedge pink, farewell summer…
Tips for successfully growing your own soapwort
The natural tendency for soapwort to spread means it is best suited to an informal garden setting, or a cottage style garden where its rampant tendencies will not spoil an ordered border. The Royal Horticultural Society recommends full sun in a well-drained soil, though it isn’t fussy about its aspect or exposure. A mix of chalk, clay and sand provides the best soil, with a neutral or alkaline pH. My experience is that it grows pretty much unchecked wherever planted, but does need summer watering to do well. It is disease-free and, in my garden, the slugs and snails ignore the mature plant. They can be grown from seed and from division, though I have had success with cuttings too. Plant seeds and young plants after the last frost, and at least 25cm apart.
What Makes it Soapy?
Saponins are water-soluble glycosides with a distinctive foaming characteristic that are found in many plants. Soapwort contains 5% saponins, which can increase to 20% in the roots in summer when the plant is flowering. Rubbing the leaves produces a slippery froth, and boiling the root and leaves in water produces a green, rather herbal/spinach-smelling liquid lather, which has gentle cleaning properties.
Harvesting the plant and making soap
Although the plant can be harvested earlier in the year before flowering (when it first reaches over 20cms or so), it produces less lather than in the height of summer. For best results I recommend harvesting when they are in full flower for the highest saponin content. The whole plant can be used to make soap, but the roots contain the most saponins. The roots can be harvested in autumn and chopped and dried for year-round use. Dried root can also be purchased fairly easily.
You can experiment with the quantities to create richer, soapier mixtures for different purposes. Soapwort makes a gentle hair wash, and is said to be an excellent soap for those with sensitive skins (please do your own tests). Traditionally it was used to clean clothes, particularly the most delicate and fragile.
For shampoos, try adding dried or fresh chamomile flowers, rosemary or lavender.
[Photo: Heather Ford]
My Experience of Using Soapwort
My experience in making detergent from soapwort suggests that it is that it is best to allow the mixture to stand overnight for maximum soapiness. It should also be said that the mixture from fresh plant is bright green! I’m not sure how those Tudor lace cuffs fared with this mixture, though they may well have used the dried root. You shouldn’t expect it to feel like modern soap - there is plenty of froth, but much less of the ‘soapy’ feel in the liquid. However, it does clean effectively.
As a shampoo, it feels like a rinse, but with a good scrub it will get hair clean. I used it as a scrubby shampoo/rinse with no other shampoo or conditioner. It left my hair feeling clean but a bit heavy. However, after a second wash a few days later with my normal shampoo, my hair was noticeably brighter and shinier. Even my partner noticed (and he's not one for remarking on such things), so it might be good for an alternate wash routine.
Soapwort and its Historical Uses
Soapwort ('Struthium') is an ancient soap with a history of varied uses in different countries and ages. Dioscorides, in his Materia Medica (1st century CE), described soapwort being used to treat wool,
‘…Struthium which fullers use for cleaning their wool’.
The French name for soapwort was ‘herbe à foulon’ or Fuller’s Herb. It was used by fullers to clean, soften and preserve the cloth. Fullers were still using soapwort as part of the finishing process in cloth production in the Middle Ages, and the same use was also be found in ancient Syria.
In ancient Rome it was used as a water softener, whilst in the Swiss Alps it was a sheep wash, and in the 13th century Italian monks used it as a disinfectant. The ruffles and lace of Tudor England were cleaned in soapwort, quite possibly for its ability to safely clean the most delicate fabrics, and because it is said to add a lustre to cloth.
[Soapwort is also known as ‘Bouncing Bett’, said to be for
the rhythmic movement of the washerwomen who used it…]
SOAPWORT AND TEXTILE RESTORATION
The National Trust has used soapwort to clean their most delicate textiles. During the 1930s the fabrics and furnishings of what was to become one of its treasured buildings, Uppark House, were restored by Lady Meade-Featherstonehaugh in collaboration with the Royal School of Needlework. In doing so they developed new techniques for textile restoration, including the use of soapwort,
‘The fragile yet filthy window and bed curtains [were cleaned]… "by being pulled over dewy grass" or by immersion in water infused with the herb soapwort’. *
She went on to share her fabric restoration techniques, lecturing world wide, and they continue to be used by textile restorers to treat the most fragile fabrics.
Soapwort and the Turin Shroud
The history of the Turin Shroud is contentious, and many have sought to find its origins and significance. The historic use of soapwort by fullers to treat textiles has played a part in unravelling this mystery…
[Photo: By Unknown author - photographed at Saint-Sulpice, Paris, Public Domain,]
The primary question raised by the Shroud regards the identity of the figure encased in the Shroud and the mysterious ever-red stains of blood. The secondary question is how this crisp, if faint, impression was made on the cloth. This last question now appears to be reaching a resolution. Ray Rogers, a member of the 1978 team allowed to examine the Shroud in detail, proposed that the Shroud was treated with soapwort (Saponaria) as a softening agent traditionally used in the processing of the ancient linen. Together with the crude starch also used on the cloth, this left a thin coating of impurities on the cloth surface, and demonstrated that exposure of Saponaria-treated linen to ammonia vapours resulted in the colouring of threads. The Saponaria treatment may also explain why certain areas of blood on the Shroud remained red (Saponaria is haemolytic – causing the rupture of red blood cells). It is also a potent preservative, possibly explaining the uniquely well-preserved status of the image and suppleness of the cloth.
If you want to dig deep into the soapwort/Saponaria history of the Turin Shroud, there is a treasure trove of detailed information in the Resources below.
Tips and Cautions
Despite the fact that soapwort has long been used as a herbal medicine, and saponins from soapwort are traditionally used to emulsify the sweet confectionary halva and to create a foam in beer, they can be toxic when ingested at high levels and harmful to aquatic life. Whilst a safe alternative to some soap uses, it is not safe to ingest unless under the supervision of a herbalist, and the soap should not be discharged into fresh watercourses.
Soapwort is an easily-obtained pure and natural soap for cleaning delicate fabrics which also works well as a mild shampoo. Easy to grow and attractive to look at, it is much-beloved as a useful cottage garden herb, and is also a living testament to our most ancient uses of natural plants.
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More on the history of laundry and clothing care here
The Turin Shroud: