Underground network for plants (5)

I believe the answer is:

roots

(Other definitions for roots that I've seen before include "Genealogy" , "Shows enthusiastic support for" , "Origins, of plants or people" , "one's ancestry" , "eg Parsnips" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.