Yarrow

Yarrow is Achillea millefolium, and both halves of the name are informative. Millefolium, thousand-leaf, describes the finely divided feathery foliage exactly. Achillea records the tradition, reported by Pliny among others, that Achilles used the plant to treat his soldiers' wounds, a story that fixes the plant's reputation in the classical period, whatever its historical value.

The wound reputation is not empty. Yarrow has a documented styptic action, and the English folk names (soldier's woundwort, staunchweed, nosebleed, carpenter's herb), all record the same use across centuries. It contains achilleine, along with tannins and flavonoids, and a plausible mechanism involving shortened clotting time has been described. This is at the more credible end of traditional wound care.

The plant is also an aromatic bitter and a traditional diaphoretic, taken hot to break a fever by sweating, which is what Culpeper describes.

Two cautions belong in a factual account. Yarrow contains small amounts of thujone. And it is a notable cause of contact dermatitis in sensitive people, and of photosensitisation, sufficient that it is a recognised occupational irritant among those who handle it in quantity. It is also easily confused in the field with several dangerous umbellifers at the rosette stage by inexperienced foragers, though the foliage and flower structure are quite distinct once known.

Yarrow is not an umbellifer, despite appearances. The flat-topped head is a corymb of many small composite flowers, and the plant is in the daisy family, each apparent petal is a complete ray floret. The resemblance to hemlock and cow parsley is convergent and superficial.

Yarrow is the clearest example in this collection of a correspondence that is genuinely contested rather than merely unsourced, and it is worth setting out why.

Culpeper gives yarrow to Venus, and Libra follows by rulership as her air sign. His grounds are the plant's use in women's complaints and its cooling, astringent character, which is the standard Venus profile in his scheme.

Against that, the plant's entire English folk identity is martial. Soldier's woundwort, staunchweed, the Achilles legend, the battlefield use, the association is with wounds, blood and war, which is the Mars category in any planetary system. A number of later compilers accordingly place yarrow under Mars, and they have the better of the argument on the folk evidence while Culpeper has the printed source.

Neither position is a corruption of the other. This is what a real disagreement looks like: two defensible readings of the same plant, weighted differently, with no arbitrating authority. It is better content than a manufactured reconciliation, and the honest statement is that yarrow is attributed to Venus by Culpeper and to Mars by others, and that the reader should know which is which.

There is a third use with no bearing on either. Dried yarrow stalks are the traditional instrument for consulting the I Ching, in the older and slower method that preceded the three-coin technique. Fifty stalks are used, manipulated through a lengthy division procedure to generate each line of a hexagram. This is a Chinese divinatory practice of considerable antiquity and has no connection whatever to European planetary herbalism; the plant is simply a suitable stalk.