Rosebay willowherb, also known as ‘Fireweed’ or ‘Bomb weed’ is a native plant that is highly invasive
Rosebay willowherb is also known as ‘Fireweed’ for a reason!
An interesting fact about this invasive weed is it will grow on burnt ground. Its seeds can settle deep in the soil and remain viable for many years and the hairs on the seeds act like (and can be used for) tinder, hence being known as ‘Fireweed’. Its ability to grow on rough or damaged ground makes it a threat to other native plants. We’re seeing dense colonies springing up all over the UK that need controlling or eradicating completely.
Is it getting out of control?
As climates change to be more extreme, ecosystems become a battlefield of the fittest for many plant species. Non-native invasive species tend to fare better but we’re finding some of our native plants are becoming dominant, and a problem for control.
This summer is untypically mild and wet right now, but when the weather changes (as predicted) to higher temperatures and dry conditions Rosebay willowherb is one of the resilient fighters. Even after a wildfire the seeds will remain viable and regrowth can begin even in a charred landscape. We predict an increase of prolific and larger outbreaks of willowherb across a wider landscape this growing season and possibly next. Councils are especially keen to get this weed under control with effective Amenity Weed Management.
What is a ‘pioneer weed’?
Scientific name; Chamaenerion angustifolium, is a tall perennial native to the UK and known as a pioneer weed – known for their ability to be the first plant to pop up on ground that has been previously destroyed. Rosebay willowherb adopted the nickname ‘bomb weed’ during the war as it was the often the first plant to establish on a bombsite. They are adapted to grow in hot, dry, and exposed conditions, and often in very poor soil conditions.
Seeds travel up to 20 miles
Seeds have a plume of small hairs and are wind dispersed. It has been recorded that a staggering 20% to 50% of seeds may be carried up to 100 metres by the wind and some could potentially travel over 100 kilometres (60 miles). This makes control extremely difficult, as new colonies quickly establish miles away from the original infestation.
Still viable 20 years later
As well as seeding on the wind, each plant develops an extensive root system by which it can quickly establish a dense mass on a piece of waste ground turning the area into a pink sea of florescence. Root fragments as little as 10-15cm can regenerate and produce new shoots and it has been recorded that even a twenty-year-old root can produce viable buds if the land is sufficiently disturbed.
Highly invasive, a nightmare for construction, landowners and councils
Rosebay willowherb can be very difficult to get rid of, as mentioned above its root system regenerates easily, so every part of the plant must be removed. This is one to watch out for on construction or development sites, to avoid future regrowth after the build is complete.
We also see a lot of this weed on our amenity contracts as it likes to grow in urban environments. Most commonly found on waste ground and gap sites throughout the UK, it also enjoys damp woods and rocky places. Regular treatment programmes need to be scheduled in with a qualified contractor to ensure this weed is under management.
Getting rid of Rosebay willowherb
As mentioned this invasive plant is notoriously difficult to eradicate. Herbicide application is the most effective, but with its shallow root system mechanical hand pulling is also a good option as long as all plant material is completely removed. Invasive plant specialists should be contracted in to treat or remove infestations before it takes over.
If you’d like us to carry out a survey or provide a quick quote for getting rid of Rosebay willowherb contact us via the form below: