Definition of iron-grass in English:

iron-grass

noun

  • Any of various grasses or grass-like plants with tough, wiry stems and leaves; especially (English regional) knot grass, Polygonum aviculare, and (Australian) any of various plants of the genus Lomandra (family Asparagaceae).

Origin

Mid 18th century; earliest use found in Patrick Browne (c1720–1790), physician and botanist.