Answer: biennial

AnswerCrossword Clue
BIENNIAL

Plant living two years

BIENNIAL

Plant that lives two years

BIENNIAL

Like national elections

BIENNIAL
Happening once in two years.
BIENNIAL
Describing H.R. elections
BIENNIALOccurring every other year
BIENNIALLike House elections
BIENNIALPoison hemlock or Queen Anne's lace
BIENNIALLasting two years
BIENNIALLike congressional elections
BIENNIALOccurring every second year