Many plants that are maligned as weeds are actually highly beneficial, with a long history of use by humans. After hearing about a friend’s determination and challenges in eradicating horsetail from his yard and listening to his children mimic his “I hate horsetail” mantra, I felt compelled to point out the practical and important uses of this botanical oddity.
Common horsetail (Equisetum arvense) is one of the most widespread and ancient group of plants that grew to an impressive size of up to 75 feet when dinosaurs roamed the earth. Several types of Equisetum species grow in the Pacific Northwest, but all were used interchangeably for practical, edible and medicinal purposes.
Horsetail is unique among vascular plants in that it has a brown spore-bearing stage of the plant and the more familiar green “bottle brush” stage. According to ethnobotany literature, both stages were eaten by Northwest Native Americans, who picked and ate the young plants raw or with oil, after removing the papery sheath.
One reference book mentions that the ancient Romans ate young, fertile horsetail shoots as if they were asparagus, and, in fact, horsetail greens are high in calcium, magnesium and sulphur.
The cell walls of horsetails are impregnated with silicon dioxide. This led to its early use by aboriginal cultures primarily as an abrasive for polishing wooden objects. The common name “scouring rush” was given to horsetail because it was used in Europe to scour utensils made of wood or pewter.
The amount of silica concentrates as the plant matures; therefore, the plant should be harvested only while the branches still point upward. I’ve heard other wildcrafters say “never pick it past three o’clock,” referring to the position of the leaves on the stem, which begin by pointing upwards and slowly droop.
Horsetail is an excellent example of an herb that you are better off collecting and preparing remedies yourself, since much of the horsetail harvested commercially is collected past its prime.
Horsetail is styptic, meaning it helps stop bleeding, and has a long history of use in treating battle wounds. It is recommended as a poultice for hemorrhages and as a tea for internal bleeding. As a topical wash, it is said to be antiseptic and disinfectant. Horsetail tincture is a traditional remedy for bronchitis and tuberculosis.
For lung disorders, horsetail is frequently combined with coltsfoot, plantain and nettle, all of which can be wildcrafted right here on Vashon. Horsetail is a mineral-rich bath herb and is reputed to increase circulation. It is especially useful for varicose veins. A decoction of horsetail is said to stimulate hair growth and eliminate dandruff and head lice.
One interesting use for horsetail derives from its affinity for gold in liquid solution. Since horsetail concentrates gold more than most other plants, it has been used in bioassays for the metal.
Horsetail’s vegetative stems have historically been used as a source for yellow-green dyes. Spraying plants with a horsetail decoction protects them from fungal diseases.
A word of caution for those of you who will try horsetail now that you know it is edible and medicinal: While the white inner core of the tan reproductive shoots are safe eaten raw, the green vegetative stalks should only be eaten after cooking. Also, since it readily uptakes the water it is growing in, it is very important to collect only from unpolluted sources.
It is important to remember that our view of plants is tainted by our lack of understanding about their historical relationship with humans.
Keeping that perspective when we are tempted to malign plants in front of our children is a gift we can give them. Instead of passing on our biases, we can allow them the opportunity to experience that all plants have their proper place in the ecosystem and that all plants deserve respect even if they are not our cup of tea.
— Erin Kenny is co-founder of the nonprofit Cedarsong Nature School.