Yes, SHADBUSH is a Scrabble word!

Letter values in Scrabble US: S 1, H 4, A 1, D 2, B 3, U 1, S 1, H 4.

Is it a valid word?

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

any of various North American trees or shrubs having showy white flowers and edible blue-black or purplish fruit

Also: service tree.

Not playable in Scrabble US: JUNEBERRY.