Carex spissa

A gray, perennial, grass-like sedge that grows along creek channels. Very dramatic specimen plant for a conventional garden or wet native garden. Plant in cobble for a creek effect, plant with other Carex species, Mimulus species, (that is where the old separation between moist Mimulus and dry Diplacus is apparent), Juncus, Satureja, Stachys, and Anemopsis. Carex spissa and Carex senta look nearly identical (the difference is in the flower parts). For your purposes, C. senta grows in all soil types and is smaller, while C. spissa grows in heavier soils, in particular serpentine-based soils.