Teasels, Dipsacus fullonum and Dipsacus sativus, in the teasel family, Dipsacaceae, for centuries were essential to the clothing industry. Today, in North America, they are noxious weeds.
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| teasel showing the seed heads |
Teasel plants are generally biennials, producing big leaves the first year, growing tall and flowering the second year, dying after flowering. They can grow 6' high. The flower heads are coarse, protected by spines, soft when flowering, scratchy as the seeds ripen inside. The white, pink or purple flowers open in ring.
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| Teasel flower, from wikipedia |
Teasel heads were used in cloth production for centuries. Freshly woven cloth is somewhat loose and irregular. It was routinely fulled to make it denser and more compact; fulling applied pressure, heat and friction, by hand, then by machine as machines were developed, so that the cloth, especially wool cloth, matted and compacted. This made a much nicer, more even cloth, but often with a pounded, compressed look and some irregularities. So the cloth was then teased. Teasing pulled the top layer back and forth, fluffing it. Excess was cut off until a nice surface, more attractive and better at holding heat, was produced. The stiff, scratchy seed heads of teasels were used for teasing. They were fitted into cards, later into drums that turned, until they were replaced by wire and plastic heads in the 20th century. While teasels were an essential of cloth production, selection for strong, symmetrical heads produced better teasels, sometimes considered a separate species, sometimes a subspecies, Dipsacus sativus, with heads that were squarer than the wild varieties and that had recurved spines to grab the cloth fibers better than the straight spines of the wild type. Thousand and thousands of teasel heads were needed as the cloth industry expanded and they were soon grown in fields all over Europe. Today, they are still used by cloth producers for very fine products such as cashmere (link)
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| common teasel Dipsacus fullonum |
The seed heads are distinctive and attractive. In addition to their industrial use, they were frequently grown in gardens and used in flower arrangements, but in the United States teasels have become very invasive, so are not sold much any more.
Teasels are seriously weedy, and are listed on state noxious weed lists all over North America. The big leaves smother the neightbors, the seed heads produce hundreds of seeds to invade new areas.
The plant has been a minor medicinal, the roots soaked in alcohol and used to treat small wounds, eczema, and rheumatism. None of the treatments has been experimentally validated.
The leaves catch water at their base. The water has long attracted attention. People used it as a wash for weak or sore eyes. Botanists have suggested the water prevents insects, slugs, and snails, from climbing on the stems to consume the plant. This has the problem that the plants are covered with prickles which deter insects and that the cups dry out in midsummer, but has not been experimentally tested. Others saw the small dead insects floating in the water and wondered if teasel was carnivorous, absorbing nutrients from the decaying insects. This discussion has been ongoing since at least the investigations by Charles Darwin's son Francis (link). A paper by Shaw and Shackleton (2011) found more seed production when they fed mealworms into the water; a paper by Krupa and Thomas (2019) found no effect of nutrients from insects in the water. Krupa and Thomas critiqued hypotheses about the function of the water-holding cups, concluding, because of evidence against alternative theories, that protection from animals that would eat it is the most likely. The function of the water-holding cups at the base of teasel leaves remains unclear.
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| big teasel plant |
Three teasel species, common teasel (Dipsacus fullonum), cutleaf teasel (D. laciniatus) and fuller's teasel (Dipsacus sativus) are found in North America, the first two widely distributed, the third on the East and West Coasts. Keys for separating common teasel and cutleaf teasel in my region (Flora of Colorado, Flora of Nebraska) say cutleaf teasel leaves form a cup where they meet the stem which collects water, but common teasel does not. That does not make sense to me because studies of the function of the water collected at the base of the leaves listed above both used common teasel. In addition, the US Forest Service description of the two species has a picture showing water collected at the leaf base of both of these species (scroll down to photo link). Krupa and Thomas (2019) say you can see a water-collecting cup in all three teasels found in North America. I don't know the right answer here.
The name Dipsacus is based on the Greek dipsa for "thirst," referring to the water in the cups formed by the leaves. The species epithets and common names are confusing. The species epithet fullonum mean's "fuller's," that is, the teasel fullers used to tease the cloth. However, the new species produced by humans selecting ever better teasing teasels is called Dipsacus sativus, sativus meaning "cultivated." Dipsacus fullonum is the wild plant used by fullers, D. sativus the actual "fuller's teasel." You see fuller's teasel used for D. sativus, but the USDA website gives Indian teasel as the common name for D. sativus. That common name doesn't make much sense to me; it is not Native American, and if it came from the subcontinent India it also came from Europe, why call it Indian?). Not everyone recognizes Dipsacus sativus as anything other than a variant of common teasel, in which case they call the cultivated teasel Dipsacus fullunom var. sativus.
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| teasel plant flowering |
References
Ackerfield, J. 2023. Flora of Colorado. 2nd edition. Denver Botanic Gardens. Denver, Colorado.
Oxford English Dictionary, s.v. “tease (v.1)” June 2024, https://doi.org/10.1093/OED/9891488002.
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