HomeBlog – How Stean Blog March 2016

How Stean Blog March 2016

Dog’s Mercury

For sure we all know best what signs tell us personally when spring is just around the corner.  For some it is surely the haunting cry of the curlew or aerobatic antics of the lapwing but flowers can equally be a harbinger of what, for me at least, is my favourite time of year. After the cold (well usually), wet, dull, dank winter it’s just great to see our flowers blooming again. Snowdrops are great, so are croci and daffodils, and each is important as an early food source for early insects. Sometimes it’s difficult to say whether these plants are wild or cultivated varieties, but there are others which certainly aren’t cultivated and which adorn any woodland floor and How Stean Gorge is no exception. Dog’s mercury (Mercurialis perennis) is easily overlooked. Easily overlooked because it’s green with spears of small greenish flowers. Dog’s mercury is also known as boggard posy. There’s not much going for dog’s mercury, it smells, it’s pretty boring looking and most of all it’s poisonous, really poisonous. Within a few hours of consuming it it can cause vomiting, pain, gastric and kidney inflammation, and sometimes inflammation of the cheeks and jaw (“malar erythema”) and drowsiness. Indeed it was recorded as early as 1693 to cause a family of five to become seriously ill and one of the children died some days later as a result. Apparently they boiled it first and then fried it with bacon (don’t do this at home!). The father of the family described his experience as “he thought his chin had bin all the day in a fire, and was forced to keep his hat full of water by him all day long and frequently dipped his chin in it.” For botanists dog’s mercury causes another problem, despite growing no taller than a foot, it shades out other plants such as oxlip and orchids.

Culpepper mentions dog’s mercury and says despite its name Venus not Mercury owns the herb, “I am partly confident of it too, for I never read that Mercury ever minded women’s business so much.” I am not sure what this means either but he goes on to say after preparation it purges choleric and waterish humours. If you are unsure what humours are, it’s probably best to remain ignorant, if you must know, then trawl through this The Free Dictionary link. Hippocrates commends it wonderfully for women’s diseases and applied it to the secret parts to ease the pains of mother; and used the decoction of it both to procure woman’s courses and to expel the afterbirth.

Anyway, I’m not sure I’m selling you dog’s mercury and maybe even convinced you there are more positive signs of spring. Look for the delightful, beautiful, yellow wood anemone. Watch the trees, now festooned with catkins, and soon I expect to see pussy willow and already green shoots are appearing on some branches, for example hawthorn. Hopefully most birds are not nesting yet, but a few may be, including rooks and crossbills, whilst most of our familiar birds if not actually nesting will certainly be prospecting for mates, defining their territories and searching out suitable nesting sites, so don’t delay in putting up your new nest boxes. Listen to the birds starting to sing instead of calling, listen especially for the great tit and it’s distinctive ‘teacher, teacher’ call, another sure sign that the seasons are changing, but beware whilst some of these spring events are happening in Lower Nidderdale, spring can be two weeks later in Upper Nidderdale, enjoy it twice.




Mabey, Richard, Flora Britannica, Sinclair-Stevenson, London, 1996, pp256–257. ISBN 1-85619-377-2

Culpeper’s Herbal, first published 1653

Nigel Heptinstall (Outdoors2015)