Yes, RICHWEEDS is a Scrabble word!

Letter values in Scrabble US: R 1, I 1, C 3, H 4, W 4, E 1, E 1, D 2, S 1.

Is it a valid word?

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

erect perennial strong-scented with serrate pointed leaves and a loose panicle of yellowish flowers; the eastern United States
a plants of the genus Pilea having drooping green flower clusters and smooth translucent stems and leaves

Also: horse balm, stone-root, stone root, collinsonia canadensis, dead nettle, pilea pumilla.

Not playable in Scrabble US: STONEROOT.