Yes, PEONY is a Scrabble word!

Letter values in Scrabble US: P 3, E 1, O 1, N 1, Y 4.

Is it a valid word?

PEONY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

any of numerous plants widely cultivated for their showy single or double red or pink or white flowers

Not playable in Scrabble US: PAEONY.