policeman's helmet

Definitions

1. The invasive plant Impatiens glandulifera, native to the Himalayas.
   UK, uncountable
2. Used other than figuratively or idiomatically: see policeman, helmet.

Examples

“Of the nonnative species, only the policeman's helmet (I. glandulifera) has a similar floral structure⟳, though its flowers are normally purple to blue and occasionally white; its leaves and stems can be used similarly to our native species.”

CEFR level