Slender Rush can be identified as a perennial grassy weed with tufted, round stems. Its lower leaves are shorter than the stem and feature flat blades. Slender Rush also includes sheaths with conspicuous, papery margins. Slender Rush has a seed head with separated flowers. The leaves at the top of the stem are longer than the seed head and this lawn weed fruits in summer.
This lawn weed thrives in most parts of North America and is often found on or in roadsides, home lawns, compacted soils and shaded areas. These perennial grassy weeds can germinate and spread from seeds, but they also produce a root structure (tubers, bulbs or corms) that can birth new weeds from your lawn's surface (using stolons) or from underground (using rhizomes). Perennial grassy weeds live two or more years and have a deeper root structure that can give rise to new weeds—even if you no longer see the weeds in your lawn.
Weed control treatments are not particularly effective in getting rid of this grassy weed. Instead, cultural control methods—such as hand-pulling lawn weeds, digging up roots and proper watering and mowing routines—are recommended.