The Common Horsetail (Equisetum arvense) or Scuab eich ghoirt in Irish is about to begin its journey of growing and propagating itself after lying dormant and underground over the winter. Just now its white or pale brown fertile stems are appearing above ground bearing egg-shaped cones full of spore capsules (1). In about a month’s time it will produce green, grooved, hollow stems with toothed sheaths on which whorls of side branches occur with regular spacings between them. These are non-fertile. Their sole purpose is to photosynthesise in order to provide food for the plant.
This plant, which is common on roadsides, waste ground, the sides of railway tracks and in some gardens is difficult to eradicate because the root system is extensive and deep often up to two metres underground (2).
Some people confuse it with a similar looking plant called Mare’s tail (Hippuris vulgaris) which grows in water.
They belong to a unique family of plants which are amongst the oldest on the planet because they appeared between 300 and 400 million years ago. They are closely related to ferns which also reproduce using spores (3). Horsetails were plentiful during the Carboniferous Period which occurred c.280-340 million years ago. Back then on the eve of the Age of Dinosaurs their giant ancestors grew c.30 metres tall in thick, swampy forests. Over time these died, and their compressed, decomposed forms turned into coal.
Horsetails have the unusual ability of absorbing silica from the ground, and this accounts for their rough, gritty texture. (Sand is made from silica). In olden days it was used as a scouring agent and also for polishing wood and metal.