Assertion: ragwort | /r/HasProperty | introduced into oregon
Facets:
value: in the early 1920s
type: TEMPORAL
value: unintentionally
type: MANNER
Source sentences:
text: Tansy ragwort was unintentionally introduced into Oregon in the early 1920s, and within 30 years, became a regional problem, killing thousands of livestock animals — mostly cattle and horses, and contaminating pastures and hay.