Assertion: fern's rhizome | /r/HasProperty | underground
Facets:
Source sentences:
text: Cinnamon fern spreads slowly via underground rhizomes that get tough and woody with age.
text: Ostrich fern spreads by underground rhizomes and can be controlled by regular division to keep them in check.
text: Ostrich fern will spread fast by underground rhizomes, thus it is an exceptional shade ground cover where it has room to roam, and intermingle with equally vigorous shade plants.