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Canada Thistle
Cirsium arvense
In the United States:
Invasive
· also called creeping thistle, field thistle
Listed as invasive. Check local regulations — several jurisdictions restrict planting.
Honeybees visit Canada thistle primarily for its abundant white pollen and moderate nectar supplies during the peak summer bloom in temperate regions. Flowers open successively over several weeks, providing a consistent foraging resource amid the plant's spiny foliage, which does not deter pollinators. As a rhizomatous perennial, it spreads vigorously and benefits from regular cutting or mowing to manage growth while preserving bloom patches for bees.
| Nectar | medium |
|---|---|
| Pollen | high |
| Bloom (US) | June–September |
| Duration | ~3 months |
| Type | Perennial |
| Sun | full |