- Solitary flowers at the end of a 20cm-2.5m tall stem
- Alternate leaves, waxy cuticle
- Flowers are purple-red, and at the base of the head are spiny bracts
- The name ‘nodding thistle’ comes from when the mature flower head falls off.
Consequences of invasion
- Likes neutral to acidic soils and is a problem in grasslands where grazing animals favour grasses over the thistle, giving it an advantage
- Outcompetes native grasses
- Creates impenetrable thickets
How was it introduced? How does it spread?
- Native to Europe, this thistle is known as a pest to rangeland
- A thistle plant may produce up to 1200 seeds
- Prefers to establish on disturbed sites.
Integrated Pest Management Options
- Prevent seed production
- Learn to properly identify nodding thistle
- Clean equipment and gear before leaving an infested site
- Dispose invasive species properly at designated disposal sites
- Frequent cultivation
- Hand digging and mowing over a period of time
- Mowing just before seed to reduce seed production. Debris from mowing should be collected and burned
More information available:
- ISCBC Nodding Thistle Photo Gallery
- USDA Mus/Nodding Thistle
- Invasive Species Council of Manitoba – Nodding Thistle