Not to be confused with the Canadian rock band from the 1970s, this rush, Juncus patens, is native to riparian areas between western Washington and San Diego County. It is also known as the common rush because it is, obviously, the most common species of the genus on the West Coast. It is only occasionally planted intentionally, but more often sneaks into well irrigated landscapes.
Those planted intentionally are mostly cultivars with slightly bluish or grayish foliage, such as ‘Elk Blue’, ‘Occidental Blue’ and ‘Carmen’s Grey’. Those in the wild, or that sneak into landscapes from the wild, are dark green like avocado skin. The upright foliage is really very slender stems that look more like leaves than the vestigial leaves do. It forms dense clumps about one to three feet tall.
Although it is a riparian plant that survives soil saturation and inadequate drainage through winter, rush can survive as soil drains and dries somewhat through summer. It prefers somewhat regular watering in landscapes and home gardens. If cut back to the ground at the end of winter, and perhaps divided, fresh new growth regenerates through spring. Growth is sparse and floppy in shade.