Nettles

The most widespread plant is the native European nettle. Rugged in appearance, with shaggy leaves, they give an itchy sting. It's true that wherever humans go, nettles follow. This is because nettles are created in soil with phosphate and nitrogen by waste. A variety of creatures including butterflies eat them. Also nettles are part of human diet too, such as soups and tea.
Nettles are considered one of the nine plants in the 10th Century English poem "Nine Herbs Charm". This is about medicine plants that treat all manner of horrible pains and infections. The nine herbs are:

Mucgƿyrt 
Attorlaðe
Stune
Ƿegbrade
Mægðe
Stiðe
Ƿergulu
Fille
Finule

The Stiðe mentioned on the list means Nettle. The prose that comes with the "Nine Herbs Charm" is:

A snake came crawling, it bit a man.
Then Woden took nine glory-twigs,
Smote the serpent so that it flew into nine parts.
There apple brought this pass against poison,
That she nevermore would enter her house.

Nettles are full of nutrients and mostly water. They can be cooked and mixed with vegetables, used as a puree and paste, added to stock and as a condiment.
Getting a sting from nettles is unpleasant. Natural treatments for stinging nettle pain and itchiness are dock leaves, that are often but not always found near nettles. As a kid, I suffered painful stings from nettles and my grandmother rubbed the area with a dock leaf, which healed instantly.