Juncus planifolius is a species of rush, commonly known as broadleaf rush, broad-leaved rush, or grass-leaved 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. In North America, it is recognized by its unbranched stems, basal leaves with no sharp demarcation of sheath and blade, and blackish tepals.