Dog's Mercury

Mercurialis perennis

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  3. Dog's Mercury


A common plant often seen carpeting the floor of ancient woodlands, Dog's Mercury can quickly colonise and spread by its underground rhizomes (stems). It can be so expansive that it shades woodland floors and crowds out rarer species like Fly orchids and Oxlip. It produces small flowers from February to April, but leaves can persist throughout the year.

How to identify

Dog's Mercury has spear-shaped, toothed, fresh green leaves carried on upright stems. It produces a foul and rotten smell and bears clusters of small, greenish flowers in spring.

Where to find it

Widespread throughout mainland UK.


When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

The Wildlife Trusts manage many woodland nature reserves sympathetically for a range of wildflowers. A mix of coppicing, scrub-cutting and ride maintenance open up the woodland floor to the sun, helping many flowers and plants to thrive and keeping others that spread easily, such as Dog's Mercury, under control. You can help too: volunteer for your local Wildlife Trust and you could be involved in everything from traditional forest crafts to raising awareness about woodland wildlife.

Species information

Common name
Dog's Mercury
Latin name
Mercurialis perennis
Height: up to 35cm
Conservation status