At this time of year, there’s not much growing, but there are still a few hardy weeds around that are used as herbal medicines. Yarrow (Achillea millefolium) is one of them and is easily recognisable, even when it’s not flowering, by its feathery, fern-like leaves. I see it a lot in grass verges by the side of roads; it’s not obvious, but unmistakable if you look closely.

Yarrow’s use as a medicinal herb can be traced from ancient history to the modern day, although it’s probably little known by most people. Yarrow tea is made with the whole top of the plant when it’s flowering in the summer and it can be dried and stored for a year.

The uses of yarrow are based around conditions of the blood, leading to it being called ‘master of the blood’ and as with many herbs it acts in seemingly opposite ways, as needed. It will help to stop all kinds of bleeding when drunk as a tea or applied topically, partly due to the presence of tannins. However it also promotes flow of blood in smaller blood vessels to reduce blood pressure. This relaxation of peripheral blood vessels helps to promote sweating and release of heat in a fever and so yarrow is also used as a tea to cool a fever. And so yarrow can be considered to be cooling, but only when needed – as it’s warming and stimulating to help develop a mild fever to fight a cold for example. Its general properties can therefore be applied to any condition where tissue needs toning or tightening or capillary circulation needs improving. It’s also antiinflammatory and antipathogenic, healing, helps digestion and urinary tract irritation.