Picture a dead plant that was powerful enough to be wrapped in layers of sheets to keep it from decaying, flavorful enough to be added to common puddings, and aggressive enough to be found carpeting roadsides with its golden fury. This plant is Tansy, a powerful herb that should be respected. To many, it just looks like a yellow weed, but it plays a critical role in the story of our relationship with plants. This plant helps pollinators, has been used in ancient and monastic gardening, and has a powerful paradox that makes it a healer, an invasive plant, and a garden ally.
This is not your average celebration of Tansy. This 7-part guide is intended to celebrate the good and the useful of Tansy, while restricting the harmful and the bad. We will examine the history of Tansy and learn the truth about its tales, while also taking a look at the ecological risks and rewards. We will look at the utilitarian and the danger of its chemical presence. If you’re a gardener, historian, or simple forager, this guide will help you with Tansy.
Table of Contents
- A Golden Thread Through History: Tansy’s Storied Past
- Knowing Tansy: A Botanical Snapshot
- The Chemistry of Power: What Makes Tansy Potent (and Problematic)
- Tansy in the Historical Medicine Chest: Uses and Abuses
- The Garden Dilemma: Cultivating Tansy with Caution
- Tansy Beyond the Border: Ecological Impact and Management
- A Future for Tansy? Responsible Appreciation in the Modern World
1. A Golden Thread Through History: Tansy’s Storied Past
Long before Tansy became a naturalised member of the flora lining North American highways, it had a storied history in the Old World. The plant’s name is thought to be derived from the Greek word, athanasia, meaning ‘immortality.’ This name was not a reference to the hardy nature of the tansy plant, but to its historical use in the preservation of the dead. The association of the plant with death and, for that, eternity, seems to be a theme.
In the medieval era, Europe saw the planting of the camphor-scented herb Tansy in monastic gardens because of the belief that its scent could ward off vermin, and, more contemporarily, pests. The monastic gardens, known as physic gardens, were used to cultivate medicinal plants. Tansy was used in monastic traditions to symbolize Christianity and was used in the cooking of Tansy cake in remembrance of Christ’s sufferings during the Lent season. Also, it was believed that, as a “cleansing” agent, it could help remove the heaviness of winter and the toxins associated with the salted meat diet.
When the pilgrims arrived in the New World, they used Tansy as a culinary herb. For the pilgrims, Tansy was a treasured herb that they used in their cooking. Europe had registered the Tansy Herb as an edible culinary herb, but in the New World, it evolved and developed its own ecosystem. In its new environment, it was able to create its own edges as a colonizer of landscapes.
The special thing about the Tansy herb is that it can live in both worlds, as a cultivated relic of the past and as a colonizer of the new.
2. Knowing Tansy: A Botanical Snapshot
For recognition, Tanacetum vulgare, Tansy, is a perennial plant belonging to the daisy and chamomile family, Asteraceae.
Growth and form: Tansy grows from a rhizome and reaches a height of 5-7 feet.
Leaves: Dark green, silky, and lacey, and are a strong identifier.
Flowers: In midsummer to early fall, the Tansy produces a cluster of yellow buttons with a strong, pungent smell.
The Common Tansy (Tanacetum vulgare) is easily confused with Tansy ragwort (Senecio jacobaea), which is highly poisonous to animals and has yellow daisy-like flowers with white petals. People often confuse the blue flowers of chicory with those of blue Tansy, a misnomer for Tanacetum annuum. Faithful familiar Tansy has yellow, round flower clusters and divided (fern-like) leaves.
3. The Chemistry of Power: What Makes Tansy Potent (and Problematic)
The tale of Tansy (historical uses, modern uses, warnings, and ecological achievements) primarily focuses on its essential oils. The plant can produce a myriad of biochemicals, one of which is the ketone thujone.
Thujone is a neurotoxin. It is the active (toxic) ingredient that contributes to the health risks associated with absinthe (a drink made with the herb wormwood (Artemisia absinthium) which is the reason for the hallucinations. High concentrations of Tansy Thujone are present, posing a potential threat to human health and warranting concern. Thujone is attributed to Tansy’s insect repellent and worm-expelling (anthelmintic) activities. However, thujone is also the reason for the health risks associated with eating Tansy.
In addition to thujone, other compounds in Tansy, such as camphor and borneol, contribute to the characteristic smell of the volatile oils and to their historical use as a stimulant and a carminative. Tansy’s composition is a superb defense against being eaten by other animals and insects, which is why a tansy leaf has never been seen to be eaten by insects. Its composition also breaks down slowly in soil, contributing to the phenomenon of allelopathy, the ability to suppress the germination and growth of surrounding plants. This is why the chemical composition of Tansy is so essential.
4. Tansy in the Historical Medicine Chest: Uses and Abuses
By far the most controversial aspect of Tansy is its overwhelming use. For centuries, it has been a staple of folk medicine, an herbal world equivalent to a Swiss Army knife. Factoring in modern empirical use surrounding these practices is quite essential. They show us our ability to improvise, yet the toxicity of the plants is a somewhat perilous use of resources.
Historical Applications (Understood as Historical Record, Not Recommendation):
Vermifuge: This is also its most famous use. Tansy teas, in tiny doses, would be used to forcibly remove and kill worms in the intestines. The thujone component is a potent neurotoxin for parasites.
Emmenagogue: Unlike many other traditional herbal practices, this can be pretty dangerous. This plant can stimulate menstrual flow. Because of this, it can terminate pregnancies, and the mother can die because the plant is toxic to the liver and nervous system.
Insect Repellant: This is the most modern and safe use. Dry Tansy can be hung in homes to keep flies and ants away. Additionally, the leaves can be rubbed on people, and if placed in bed, will keep mites and fleas away.
Preservative: Once again, due to Tansy’s antimicrobial properties, this plant has been used in cloth and linen burials and to deter moths.
With Tansy, the dose makes the poison, meaning there is a fine line between medicine and poison. It is documented that there are symptoms of thujone poisoning, which are violent spasms, convulsions, organ failure, and death, and can be caused by overdosing on Tansy. Because of the risk of these symptoms, modern herbalism has stopped using familiar Tansy. History has shown that it is dangerous to use this plant, and it is a perfect example of how psychosomatic symptoms are real and can be hazardous.
5. The Garden Dilemma: Growing Tansy in Caution
Let’s talk about Tansy. If you can grow it, the answer is yes, as long as you do so responsibly. Tansy is potentially toxic and invasive, so you shouldn’t grow it if you are a beginner or casual gardener.
Growing Tansy in a Controlled Setting
Insectary Plant: It is excellent for presenting a modern garden. Ladybugs, lacewings, and hoverflies can be found in tansy flowers and help boost pest control.
Pollinator Support: Many pollinators love these plants. Honeybees don’t really contribute, but a wealth of native and wild pollinators can be found visiting.
Companion Plant: Certainly, some gardeners praise Tansy for helping control other pests, like the Colorado potato beetle and squash bug.
Things to Consider if You Are Going to Grow Tansy
Each of the Below Sections is Considered Non-Negotiable
Containment: Avoid letting it seed. Be diligent in the Deadhead. You could grow it in a solid raised bed or container with rhizomes.
Location: Check whether Tansy is considered invasive or a noxious weed in your area.
Safety Precautions: Wear gloves when working, especially if your skin is sensitive. Mark your plants. Tell everyone in your home, especially children, that it is not food. Avoid food.
Disposal: Don’t compost big pieces of seedheads or rhizomes. Please put them in a sealed bag and throw them in your regular trash.
6. Tansy Beyond the Border: Ecological Impact and Management
When Tansy leaves the garden, it becomes an aggressive invasive perennial. It grows on disturbed soils, such as road edges, riverbanks, and empty fields. It spreads through rhizomes (root-like structures in plants that enable vegetative reproduction) to form dense monoculture stands. It outcompetes native grasses, wildflowers, and young trees.
Dense populations of Tansy lead to large-scale ecological impacts. They reduce native species populations, alter soil chemistry, and provide little or no nutritional support to wildlife. Animals and sometimes livestock will eat it despite the poisonous toxins it contains (thujone).
Control Measures:
Managing a Tansy infestation is a long-term undertaking. It is composed of:
Mechanical: Cutting the stems before they flower, to not allow roots to keep food (deplete root reserves). Mowing the plants for several years in a row is necessary.
Manual: For little areas, thorough digging is needed to remove the whole rhizome (root) system. Any pieces that are too small will allow the rhizome to grow new plants.
Chemical: In extreme scenarios, particular herbicide use may be the only viable management option. This is usually a last resort and must be performed by specialists, particularly near water.
The wild story of the Tansy is a cautionary tale, specifically about the introduction of non-native species into the wild; however useful they may be.
7. Tansy: Towards Responsible History in Contemporary Society
What can we say of the Tansy? Is it only to be classified as a noxious weed and destroyed, or can we develop a new, more positive perspective?
Tansy’s future probably lies in this more positively constructive perspective. It is possible to recognize the current risks of its internal uses and avoid repeating the past. Tansy can be used to provide ecological services in the garden while still being kept in a containment facility. It can also be researched.
Most current research focuses on compounds other than thujone. Could different compounds found in tansy help formulate new and improved botanical pesticides? Does its chemical activity help answer some of the questions in sustainable weed management? Given the chemical complexity of Tansy, it may still have a lot to offer, but only to those willing to do the research in the laboratory, rather than in a teacup.
Tansy endures as an influential teacher, teaching us the strong, entangled history shared between people and plants. It teaches us respect and reverence for the botanical skills that heal, harm, protect, and defend. It reminds us that most things in the natural world are not simple heroes or villains. Most things are simply powerful, and want to be understood and respected. To know Tansy is to see a piece of history and to smell a pungent history. It teaches us to look past the flowers and see a robust, complicated, and enduring legacy.
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