Agrostis capillaris
Colonial bent
(c) Jon Sullivan, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Grass · Not Native
Agrostis capillaris (Colonial bent) is a non-native California grass in the Poaceae family, recognized by ligule wider than long and widely spreading thread-like inflorescence branches.
Colonial bent is a naturalized perennial grass found in the Klamath Ranges, northern California Ranges, northern Sierra Nevada, Central Coast, San Francisco Bay Area, and southern California coastal regions in roadsides and open, disturbed places at elevations below 1,900 meters. Flowering from July to September, this grass produces delicate, open panicles with thread-like branches creating a soft, airy appearance. Growing with slender stems 10 to 75 centimeters tall and spreading through short stolons or rhizomes, it forms loose, spreading clumps. Its leaf blades are flat, 3 to 10 centimeters long and 1 to 5 millimeters wide, with distinctive ligules that are wider than long. The plant's small spikelets have glumes 2 to 3 millimeters long and lemmas occasionally featuring a short awn near the tip.
Identification and appearance
Key characters: 19 sympatric species; key feature is ligule wider than long and widely spreading thread-like inflorescence branches
Habitat and range
Habitat: Roadsides, open, disturbed places
Elevation: < 1900 m
California counties: Humboldt, Contra Costa, Santa Barbara, Alameda, Marin, Mendocino, San Francisco, Santa Clara, Ventura, San Mateo, Sonoma, Monterey, Placer, El Dorado, Modoc, Tuolumne, Siskiyou, San Diego, Orange, Nevada, Lassen, Fresno, Butte, Amador, Plumas, Yolo, Sacramento, Mariposa, Santa Cruz, Alpine, Del Norte, Glenn, Lake, Solano, Trinity, San Luis Obispo, Mono, Sierra
Outside California: to Alaska, western United States, Canada, native to Europe
Bloom period
Agrostis capillaris blooms Jul-Sep.
How to tell it apart
vs Oloptum: Oloptum has prominent bent awns; Agrostis awns are tiny or absent.; vs Holcus: Holcus has velvety-hairy spikelets; Agrostis spikelets are smooth and glossy.; vs Polypogon: Polypogon has dense bristly panicles; Agrostis panicles are airy and delicate.; vs Poa: Poa has boat-shaped lemmas with 5 veins; Agrostis lemmas are rounded with faint veins.; vs Festuca: Festuca has multiple flowers per spikelet; Agrostis has single-flowered spikelets.
Frequently asked questions
Is Agrostis capillaris native to California?
No. Agrostis capillaris is not native to California (recorded as not native).
When does Agrostis capillaris bloom?
Agrostis capillaris blooms Jul-Sep.
Where in California does Agrostis capillaris grow?
Agrostis capillaris occurs in Humboldt, Contra Costa, Santa Barbara, Alameda, Marin, Mendocino, San Francisco, Santa Clara and other counties, at elevations of < 1900 m.
What plant family does Agrostis capillaris belong to?
Agrostis capillaris is in the Poaceae family, genus Agrostis.
What habitat does Agrostis capillaris grow in?
Agrostis capillaris grows in Roadsides, open, disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.