Join a Scotch Thistle Bash!

The North Okanagan Scotch Thistle Bash is a coordinated, region-wide effort to control Scotch thistle (Onopordum acanthium), an invasive plant that spreads aggressively and can dominate grasslands, trailsides, and agricultural edges. During Earth Week 2026, community groups, partner organizations, and local volunteers will host multiple “bashes” across the North Okanagan to remove plants, prevent seed spread, and record locations for long-term management.

What is a “Thistle Bash”?

A Thistle Bash is a community work event focused on:

• Removing first-year rosettes by cutting 1 to 2 inches below the soil to destroy the regrowth point.
• Preventing seed spread by deadheading any flowering plants and bagging seed heads.
• Documenting results so the region can track progress over multiple years.

Why it matters

Scotch thistle can:

• Outcompete native plants and reduce grassland biodiversity.
• Degrade habitat for birds and wildlife.
• Reduce recreational access and enjoyment on trails and parks.
• Create serious challenges for agriculture by lowering forage quality and increasing control costs.

How to participate

You can help in two main ways:

• Join a local bash listed below, or connect with Heidi to discuss organizing
• Be “eyes on the landscape” by reporting thistle locations through iNaturalist, even if you cannot attend an event

Partners and support

This initiative is coordinated by the North Okanagan Environmental Collective, in partnership with the Grasslands Conservation Council of BC and the Invasive Species Council of BC, with participation from many local organizations, clubs, and residents.

• Allan Brooks Nature Centre: https://abnc.ca/
• Armstrong Spallumcheen Trails Society: https://www.astrailssociety.com/
• BX Swan Lake Community Association: https://bx-swanlake.blogspot.com/
• Friends of Kalamalka Lake Provincial Park: https://www.kalamalkapark.ca
• Friends of Okanagan Rail Trail: https://www.okanaganrailtrail.ca/
• Invasive Species Council of BC (ISCBC): https://bcinvasives.ca/
• Nature Conservancy of North Okanagan: https://ncno.ca/
• North Okanagan Naturalists’ Club: https://www.nonc.ca/
• Okanagan Similkameen Stewardship Society: https://osstewardship.ca/
• Ribbons of Green Trails Society: https://www.ribbonsofgreen.ca/
• Vernon Outdoor Club: https://www.vernonoutdoorsclub.org/

Media

The project and the practical management technique have been developed with support from the Invasive Species Council of BC (ISCBC). Local groups are encouraged to share this event list through newsletters, social media, and community boards.

• Event video: Watch on YouTube 
• Management technique: Watch on YouTube

Event list

Some event dates are still being finalized!

Report Scotch thistle with iNaturalist

We are building a shared inventory of thistle locations to support coordinated management over multiple years.

Project link:

https://inaturalist.ca/projects/scotch-thistle-bash

How to contribute:

• Take a clear photo of the plant.
• Make sure your phone’s location services are on so the observation includes coordinates.
• Upload your observation to iNaturalist and add it to the project.

Tips for strong observations:

• Use a “breadcrumb” approach by recording the first thistle you see, a few observations along the way, and the last one.
• Add notes like approximate abundance (for example: “20 to 50 plants observed”).
• If you prefer, take photos in the field and upload later from home to save phone battery.

Safe and effective removal of Scotch Thistle

• For rosettes (first-year plants): slice 1 to 2 inches below the soil surface to destroy the growth point.
• For flowering plants: clip and bag seed heads first, then cut stalks.
• Minimize soil disturbance where possible to reduce triggering new germination.
• Only bag and dispose of viable seed heads. Dead, brown stalks can often remain on site because they will not regrow.

Contact

For general coordination questions or to add your group’s event to this list, please contact:

• Heidi Wismath: heidi@bcgrasslands.org