Juncus effusus

Soft rush or common rush (also bog rush or mat rush) is a grass-like, rhizomatous perennial that features cylindrical upright green stems in spreading basal clumps to 20-40? tall. Clumps provide vertical accent to moist garden areas. Although the stems appear from a distance as coarse and stiff, they are soft to the touch. The plant leaves are reduced to bladeless sheathing at the stem bases. Insignificant, tiny, yellowish-green to pale brown flowers appear in clusters (many flowered cymes) that emerge on the side of the stems slightly below the stem tips in summer.