Noun: blue thistle
- A coarse prickly European weed with spikes of blue flowers; naturalized in United States
"blue thistle had taken over the abandoned field";
- blueweed, blue devil, viper's bugloss, Echium vulgare
Derived forms: blue thistles
Type of: herb, herbaceous plant
Part of: Echium, genus Echium
Encyclopedia: Blue thistle