Carex filifolia, commonly known as threadleaf sedge, is a perennial herbaceous plant native to the open grasslands, dry slopes, and rocky outcrops of western North America. It forms dense clumps of stems that can reach up to 14 inches in length, with very narrow, rolled leaves that give the plant its thread-like appearance. The inflorescences are subtle, with reddish-brown scales, and appear in late spring to early summer. While not showy, they add a fine texture to the landscape.

Threadleaf sedge is valued for its ability to thrive in a range of conditions from moist to dry, making it a versatile choice for gardeners. It is often used in xeriscaping, rock gardens, and as a ground cover in areas with poor soil. In cultivation, it prefers full sun to part shade and can tolerate a variety of soil types, though it does best in well-drained soils. This sedge is low maintenance and typically does not suffer from serious disease or pest problems. However, it can spread vegetatively and may need to be managed to prevent unwanted colonization.CC BY-SA 4.0