Yes, MULBERRY is a Scrabble word!

Letter values in Scrabble US: M 3, U 1, L 1, B 3, E 1, R 1, R 1, Y 4.

Is it a valid word?

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

any of several trees of the genus Morus having edible fruit that resembles the blackberry
sweet usually dark purple blackberry-like fruit of any of several mulberry trees of the genus Morus

Also: mulberry tree.