Polypogon viridis
Water beard grass
Photo by Chez Brungraber
Family: Poaceae · Type: Grass · Not Native
Polypogon viridis (Water beard grass) is a non-native California grass in the Poaceae family, recognized by trailing habit and awnless condition.
Water beard grass is a naturalized perennial grass found in northern coastal, Klamath Range, north coastal redwood, Sierra Nevada, Central Valley, central western, southwestern, southern Sierra Nevada, and desert bioregions in disturbed areas, wet areas, ponds, and streambanks at elevations below 3,000 meters. Flowering from May to June, this grass produces pale green to whitish flower clusters in dense, narrowly lanceolate to elliptic arrangements. Growing with long-trailing stems 10 to 100 centimeters tall that root at the nodes, it spreads extensively across wet habitats. Its flat leaves measure 3 to 18 centimeters long with blades 2 to 10 millimeters wide, featuring ligules 1 to 6 millimeters in length. The plant's flower clusters have small glumes 1.5 to 2.5 millimeters long with finely scabrous surfaces.
Identification and appearance
Key characters: 5 sympatric species; trailing habit and awnless condition are diagnostic
Habitat and range
Habitat: Common. Disturbed areas, wet areas, ponds, streambanks
Elevation: < 3000 m
Outside California: southwestern United States, native to Europe, northern Africa, western Asia
Bloom period
Polypogon viridis blooms May-Jun.
How to tell it apart
vs Lagurus: Beard grass has loose fuzzy heads in wet areas; hare's tail has dense white-woolly oval heads in dry areas.; vs Cynosurus: Beard grass has soft fuzzy bristled heads; dogtail has hard one-sided spike-like heads.; vs Hordeum: Beard grass has soft fuzzy heads; barley has stiff, harsh-awned spike-like heads.; vs Setaria: Beard grass spikelets fall intact; foxtail bristles remain on stem after seeds fall.; vs Trifolium: Polypogon is a grass with fuzzy flower spikes; Trifolium is a legume with clover-leaf clusters.
Frequently asked questions
Is Polypogon viridis native to California?
No. Polypogon viridis is not native to California (recorded as not native).
When does Polypogon viridis bloom?
Polypogon viridis blooms May-Jun.
What plant family does Polypogon viridis belong to?
Polypogon viridis is in the Poaceae family, genus Polypogon.
What habitat does Polypogon viridis grow in?
Polypogon viridis grows in Common. Disturbed areas, wet areas, ponds, streambanks.
Related species
Other California species in the same genus, family, or bioregion.
- Polypogon australis — Chilean beard grass
- Polypogon imberbis — Streambank rabbits foot grass
- Polypogon interruptus — Ditch beard grass
- Polypogon maritimus — Mediterranean beard grass
- Polypogon monspeliensis — Annual beard grass
- Polypogon sp. — Beard grass
- Puccinellia distans — European alkali grass
- Puccinellia howellii — Howell's alkali grass
- Puccinellia lemmonii — Lemmon's alkali grass
- Puccinellia nutkaensis — Alaska alkali grass
Sources: Jepson eFlora · 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.