Rosebay willowherb (Chamerion angustifolium) is tall late-summer wildflower with distinctive pink-purple flowers that grow in tall spikes from July-September, with spirals of lance-like leaves.
It flourishes in waste ground in many different soils, but always in places that have been recently disturbed.
It is common where there has been upheaval like digging, tree clearance, by roads, railways or near rivers or cliffs. It is also common in areas that have experienced recent fires – natural or manmade (hence it’s nickname, ‘fireweed’. It grew in bomb craters and following fires during WWII earning it another name, ‘bombweed’). However, it doesn’t like areas that are heavily walked or grazed – it is not trampling-tolerant.
Natural Navigation
For natural navigation it is an interesting sign that poses a puzzle. It strongly suggests that humans have been busy and therefore a clue that you are getting near civilisation, but doesn’t give the full story of what has been going on.
Direction: The plants like lots of direct sunlight and so are more likely on south-facing slopes. There is not a strong enough bias towards north or south in the flowers themselves to be used for navigation.
A few weeks ago I was leading a micro-course in natural navigation as part of a small summer festival organised by The Good Life Society. I set out into grounds of the Hawarden Estate, North Wales, like the Pied Piper, with around 30 people following in a line behind. Early on during our walk together I pointed to the large patch of rosebay willowherb you can see in the picture at the bottom of this post and said,
“Rosebay willowherb is a sign of serious recent disturbance. It is common where there has been upheaval like digging or tree clearance.”
By chance, one of those in the group owned the land we were standing on, but I only remembered this after saying the line above. I took a chance and asked them what the story was with the land we were looking at. On one level this was a bit of a gamble, if she had replied that there had been no change there for decades it would have taken the wind out of my sails and weakened the rest of the course – you can’t argue with the landowner about the recent history of the land.
But, in another important sense, it wasn’t a gamble at all. These signs are dependable, nature never lies. We can occasionally mis-interpret something or confuse something, but nature won’t mislead us deliberately, it is too busy doing its own thing. And so I knew there would be an explanation that fitted with the sign I had just explained.
“That used to be a flowerbed.” The owner said.
Not to be confused with:
Greater Willowherb. They have similar coloured petals on their flowers, but otherwise look quite different. The greater willowherb flowers have a distinctive ‘white cross’ in the middle. If you see the cross, it’s not Rosebay Willowherb. Greater willowherb is a sign of damp ground.
Notes for foragers:
It has been used to make tea in the West and beer in Kamchatka, which is then sometimes turned to vinegar.
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How to Find Your Way with Scents and Smell