One of the most striking plants of summer, rosebay willowherb is a vigorous pioneer plant with plenty to offer the forager in the warmer months of the year. As common as it may seem in the UK today, this wasn't always the case
Before the great city was rebuilt after World War II, a different kind of phoenix rose from the ashes of London. The bombed-out areas left by the Blitz were claimed by rosebay willowherb (Chamaenerion angustifolium), a plant that proves the saying: "nature abhors a vacuum". Quick to colonise and rapacious in its spread, it is also known as bombweed for its ability to capitalise on devastation, covering the "wound" in a blaze of glowing pink.
Another of its nicknames is Fireweed, particularly in the United States, where it is equally
common. It can tolerate both acid and basic soils, but struggles where nutrients are depleted, and will take over land that has been cleared by fire, which is where the name comes from. It can also be found in bare soil, open woodland, paths, roadsides, gardens, marshland and any waste ground.
Strange as it may seem to modern plant enthusiasts, rosebay willowherb was once a far less uncommon sight in the UK. It seems to have increased rapidly after the beginning of the 20th century. In one case occurring in 1909, on the Isle of Wight, rosebay willowherb appeared in great abundance on the site of a woodland that had been completely removed by fire. Prior to this, it had been uncommon on the island (Stratton, 1909).
Some botanists theorise that the sudden spread of rosebay willowherb was due to the introduction of a North American form. This form has 72 chromosomes in contrast to the 36 of the UK native form (Frankton, 1956).
Rosebay willowherb offers a spectacular display when it appears in number. Reaching up to 2.5m tall, it has long, narrow, lance-shaped leaves — their similarity to the leaves of the willow tree give the plant part of its common name — with the younger ones tinged with red at their base. The veins of those leaves are anastomose (cross-linked) creating a loop around the edge of the leaf rather than terminating at the leaf edge. This is a useful identification point, especially before flowering.
The flowers themselves are arranged on tall spikes and appear from June to September. Appearing in a range of pinks to purples, perhaps due to the two intercontinental forms mentioned earlier, they have four spoon-shaped petals crossed with four darker coloured sepals. Their similar resemblance to wild roses adds to their colloquial name.
As the flowers die off, long pods appear that release abundant fluffy seeds in the 10s of thousands, which, carried on the wind thanks to a plume of hair, spread extensively. It is estimated that 20-50% of seeds travel around 100m but some could travel up to 100km (Broderick, 1990). It also spreads via root buds.
Although it is considered a pest by some, it has many uses, both culinary and medicinal, to entice the forager. Rosebay willowherb is the gift that keeps on giving. The young shoots can be used in a similar way to asparagus, while the young leaves can be included in salads. Thanks to the high amount of tannins they contain, the older leaves tend to be rather bitter but can be dried and ground, or fermented, to make a substitute for tea. In Russia, this is known as Ivan's Chai.
The soft pith in the stems, if you can extract enough of it, makes an excellent thickener for
soups and stews. The flowers can be used to brighten salads or to make jams, jellies, cordials and alcohol infusions. They can also be used them to make a bright pink fruit syrup — though this might be rather labour intensive in terms of how many you’d have to pick. That said, another boon for the forager is the fact that rosebay willowherb grows so rapaciously that you would be hard pushed to overharvest it.
The silky threads from the seeds have been used as cordage, fibre for stuffing, even clothing and, gathered together, make excellent kindling for fires — another interpretation of the fireweed moniker.
But its uses do not stop there; according to pfaf.org, rosebay willowherb is antispasmodic, astringent, demulcent — that is, it relieves irritation and inflammation — emollient and a laxative. It can ease ulcers and skin problems, headaches, stomach cramps and muscle pain, and has been used to treat coughs, bronchitis and asthma.
And at a time when the world is trying to find new forms of sustainable energy, wildflowerweb.co.uk cites another use for rosebay willowherb. Because of its ability to spread and thrive across wide areas, researchers are exploring whether it could be used as a biofuel to power vehicles and generate electricity. Perhaps its profusion in more recent years could be more than a little timely.
Broderick, D. H. (1990). The biology of Canadian weeds. 93. Epilobium
angustifolium L. (Onagraceae). Canadian Journal of Plant Science 70, 247-
Frankton, C. (1956). Weed control and weed biology in Canada. Proceedings of the
3rd British Weed Control Conference, Blackpool, England, 165-.
pfaf.org Epilobium angustifolium
Stratton, F. (1909). Epilobium angustifoliumJournal of Vegetation Science, 23(2), 236–248.
wildflowerweb.co.uk Rosebay willowherb
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Always stay safe when foraging. You need to be 100% sure of your identification, 100% sure that your foraged item is edible, and 100% sure that you are not allergic to it (it is good practice to always try a small amount of any new food you are consuming). If in doubt, leave it out!