The clustered field sedge, known scientifically as carex praegracilis, as well as by the additional common names of field sedge and expressway sedge, is a species of North American sedge. Occurring naturally in the San Bernardino Mountains, carex praegracilis is cultivated in the specialty horticulture trade as a lawn substitute and in meadow-like plantings.
Native to much of North America from Alaska across southern Canada and throughout the continental United States, from Maine to California except for the nation’s southeastern region, Carex praegracilis grows in wet and seasonally wet environments in a number of habitats from low elevations up to 10,000 feet, including meadows and wetlands. It tolerates disturbed habitat such as roadsides and thrives in alkaline substrates. Carex praegracilis produces sharply triangular stems up to three feet in height from a network of thin, coarse rhizomes. The fine textured grass-like blades can reach 12 inches tall to form a thick weed smothering groundcover.
Under natural conditions it has a lush tousled appearance. In domesticated settings it is often trimmed to provide a low turf-like appearance. This plant tolerates drought, inundation, poor soils, salt spray, heat, cold, shade and foot traffic. It will thrive in sun and light shade, requiring some summer moisture but far less than the grasses used in conventional lawns. It will go summer dormant if allowed to get too dry. It is deer resistant.
Leaves are basal and alternate with 2 to 4 leaves all near the base of the stem, 1 to 3 millimeters wide, up to 14 inches long and mostly shorter than the flowering stems. Stem leaf sheaths tightly wrap the stem, the front translucent whitish, straight to slightly concave across the top and the tip not extended above the leaf base. The ligule, which is a membrane where the leaf joins the sheath, is mostly longer than wide. Leaves are hairless but rough along the edges, flat but V-shaped in cross-section when young, and ascending to spreading.
The inflorescence is a dense, somewhat cylindrical array of flower spikes from 1.6 inches to 2 inches long. The plant is very rarely androgynous and rather most often dioecious, meaning its individual plants bear stamens, i.e., male flowers or, alternately, carpels, i.e., female flowers in its inflorescences, but not both.
Its fruit develops in late spring through early summer, the pistillate spikes forming clusters of seeds, called achenes, each wrapped in a casing, called a perigynium, subtended by a scale. Pistillate spikes usually contain 4 to 12 fruits that are erect to ascending and overlapping on the stalk.
Pistallate scales are lance to egg-shaped, straw colored to reddish-brown with whitish edging and a green midrib drying to light brown, tapering to a pointed tip, about as long and wide as the perigynia and mostly concealing it.
The range of this sedge is spreading, especially along roadsides where the application of road salt has apparently encouraged its growth.
The butterflies and moths hosted by Carex praegracilis native to California include the umber skipper, poanes melane; the common ringlet, coenonympha tullia; the dun skipper, the euphyes vestris; the American ear moth, amphipoea Americana; the mountain beauty moth, syngrapha ignea; the American crescent borer, helotropha reniformis; the olive green cutworm moth, dargida procinctus; elachista cucullata; and the lesser wainscot moth, mythimna oxygala.
From www.calfloranursery.com, www.minnesotawildflowers.info, calscape.org/loc-San_Bernardino_National_Forest,CA and Wikipedia