Juncus planifolius is a species of rush, commonly known as grass-leaved rush or broad-leaf rush. It naturally occurs in Australia, New Zealand, Hawaii and South America.In New Zealand J. planifolius is found in open, wet ground, and can be typically found on exposed clay, beside tracks or drains.Recently J. planifolius has been introduced to the northern hemisphere. It was found in Hawai'i in 1930 and has spread to most of the islands. The species arrived in Ireland by 1973.