The bases of the stems are white with pink stripes or veins; this character has been called the "stripy pyjamas".

This species can be distinguished from H. mollis by the beardless nodes on its culm, the absence of rhizomes, and the awn becoming hooked when dry and not projecting beyond the tips of the glumes.

[3] Holcus lanatus is a significant pest weed in Australia, as it is a winter-growing C3 grass and survives droughts and hot summers as seed.

[3] In North America, Holcus lanatus is an invasive species in native grasslands and other ecosystems.

In Yosemite National Park it is one of nine priority noxious weeds to control for habitat restoration and regenerating native plant balances.

In the former it has been found as an invasive species in Sphagnum peatlands disturbed by peat extraction in southern Patagonia.

[6] Holcus lanatus in its natural habitat is a food source for butterflies such as the speckled wood, the wall, and especially the small skipper.

In its native range it may occur in plant associations such as the Juncus subnodulosus–Cirsium palustre fen-meadow habitat.