Yes, OLEANDER is a Scrabble word!

Letter values in Scrabble US: O 1, L 1, E 1, A 1, N 1, D 2, E 1, R 1.

Is it a valid word?

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

an ornamental but poisonous flowering shrub having narrow evergreen leaves and clusters of fragrant white to pink or red flowers: native to East Indies but widely cultivated in warm regions

Also: rose bay, nerium oleander.