Brass Buttons

Leptinella squalida, brass buttons, is a rhizomatous mat-forming perennial from New Zealand, growing only two or three inches high but spreading indefinitely by runners. The tiny ferny leaves are bronze-green and finely divided, forming a dense carpet. Small button-like yellow flower heads sit just above the mat in June and July.

It is one of the few plants tough enough to walk on and low enough to use as a lawn substitute, knitting between stepping stones into a carpet no thicker than moss. The trade-off is that it spreads indefinitely and has no natural stopping point, so it needs an edge it cannot cross rather than periodic trimming.