Yes, SALSILLA is a Scrabble word!

Letter values in Scrabble US: S 1, A 1, L 1, S 1, I 1, L 1, L 1, A 1.

Is it a valid word?

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

tropical vine having umbels of small purple flowers and edible roots sometimes boiled as a potato substitute; Colombia
tropical vine having pink-and-yellow flowers spotted purple and edible roots sometimes boiled as a potato substitute; West Indies to northern South America

Also: bomarea salsilla, bomarea edulis.