Yes, LOCOWEED is a Scrabble word!

Letter values in Scrabble US: L 1, O 1, C 3, O 1, W 4, E 1, E 1, D 2.

Is it a valid word?

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

any of several leguminous plants of western North America causing locoism in livestock
street names for marijuana

Also: crazy weed, green goddess, mary jane.

Not playable in Scrabble US: SESS, SENS.