Yes, MYRTLE is a Scrabble word!

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

Is it a valid word?

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

widely cultivated as a groundcover for its dark green shiny leaves and usually blue-violet flowers
any evergreen shrub or tree of the genus Myrtus

Also: vinca minor.