Yes, POTHERB is a Scrabble word!

Letter values in Scrabble US: P 3, O 1, T 1, H 4, E 1, R 1, B 3.

Is it a valid word?

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

any of various herbaceous plants whose leaves or stems or flowers are cooked and used for food or seasoning