Rosebay Willowherb (Epilobium angustifolium)
The genus name of Epilobium comes from two Greek words: epi meaning upon and lobos meaning a pod which alludes to the fact that the flowers seem to sit upon the top of long, thin pod-like seed vessels that look rather like thick flower stems. The name willowherb refers to the leaves which look rather like the leaves of the willow tree.
Rosebay willowherb was restricted in its habitat to clearings in woodland, until the advent of the railways. The disturbance of the ground by the construction of the railways and the corridors of movement which they provided allowed the rosebay willowherb to spread far and wide
Rosebay willowherb, known as fireweed in the USA and greater willowherb in Canada, rapidly colonises burnt ground. During the bombing of London during WWII, this plant often colonised derelict sites giving a much needed splash of colour during this grim time. In the later months of summer it produces lots of pollen and nectar which bees turn into a rich, spicy honey. It is the main food source for the caterpillar of the Elephant Hawk-moth. In Russia it is used as a substitute for tea, and is called kaipor tea. The leaves of rosebay willowherb can be fermented just as the leaves of tea can.
‘The willowherb will stop bleeding, heal wounds and drive away snakes, gnats and flies’ 
Picking the flower would mean your mother would die.
Thunderstorms ensue from picking the flowers.
Boys in the Thteford area used to smoke the fluffy down from the plant, but it was a very hot and strong smoke.
In Elizabethan times, fern seed was believed to be invisible, expect for a few moments around midnight on Midsummer Eve when it could be seen falling to the ground. Anyone who could catch some in a pewter plate would be invisible while they carried it (the seed not the plate!).  Shakespeare, in Henry IV, wrote ‘we have the receipt of fern seed, we walk invisible’.
In 19th century Lancashire, young people would go to Clough, near Moston, to silently gather the seeds of ‘St John’s Fern’ on the Eve of St John’s Day. They would do this in order to gain the affections of those maidens who would not accept their attentions. In Lincolnshire, St Mark’s Eve was called ‘the Devil’s Harvest’ because ferns were said to bud, blossom and release seed all between midnight and 1 a.m. and it would be the Devil that would harvest it. If anyone managed to catch some of the seed between two pewter plates, then they would become as wise as the Devil. 
In the 17th century it was believed that the burning of bracken – either in the preparation of potash (used in the manufacture of glass or soap) or for its control – would lead to rain. 
If you cut a fern stall horizontally you will see a significant letter, supposedly the initial of the person you will marry. A less common superstition, but one that was more serious, was the idea that the initial is always a ‘C’, signifying Christ, and for this reason witches are said to detest the plant. 
Another version is that the shape is a representation of an oak tree, the clearer the shape the better your luck will be .
The Druids classified ferns as sacred trees. At Midsummer, uncurled fronds of Male Fern were gathered, dried and then carried as good-luck charms. Fern leaves also have the reputation of preventing evil from entering one’s home.
- E Radford and M A Radford – Encyclopaedia of Superstitions 1949
- J Simpson and S Roud – A Dictionary of English Folklore
- R Vickery – Dictionary of Plant-Lore