Poa pratensis subsp. pratensis
Kentucky blue grass, Kentucky Blue Grass
Jim Morefield from Nevada, USA (via Wikimedia Commons) · CC BY-SA
Family: Poaceae · Type: Grass · Not Native
Conservation status: Cal-IPC Yes
Poa pratensis subsp. pratensis (Kentucky blue grass) is a non-native California grass in the Poaceae family, recognized by non-native weedy habit and dense cobwebby callus.
Kentucky blue grass is a naturalized perennial grass found throughout California in disturbed habitats, pastures, and areas with sub-saline and sub-alkaline soils at elevations up to 3,500 meters. Flowering from March to July, this grass produces small, delicate greenish-white flowers in loose, spreading inflorescences 6 to 15 centimeters long. Growing 20 to 70 centimeters tall with multiple long, stout rhizomes, it forms loose or tufted clumps with flexible stems. Its leaf blades are 2 to 4 millimeters wide, soft to firm, and typically flat or slightly folded, with open leaf sheaths and small ligules 1 to 4 millimeters long. The plant is notably adaptable, with complex chromosome variations and the ability to reproduce both sexually and asexually.
Identification and appearance
Key characters: 47 sympatric species; distinguished by non-native weedy habit and dense cobwebby callus
Habitat and range
Habitat: Common. Disturbed habitats, pastures, tolerating sub-saline and sub-alkaline soils
Elevation: < 3500 m
Outside California: northern temperate to arctic, native to Eurasia
Bloom period
Poa pratensis subsp. pratensis blooms Mar-Jul.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Festuca: Poa has boat-shaped, keeled leaf tips; Festuca leaves are flat or rolled but never keeled like a ship's prow.; vs Melica: Poa has fine, narrow leaves with boat-shaped tips; Melica has wider, flat leaves without the distinctive keel.; vs Nassella: Poa leaves have boat-shaped tips you can feel; Nassella leaves roll inward and lack the keel.; vs Koeleria: Poa has cobwebby hairs at seed base and keeled leaf tips; Koeleria lacks both features.; vs Holcus: Poa has boat-shaped leaf tips; Holcus leaves are flat and soft-hairy without any keel.
Frequently asked questions
Is Poa pratensis subsp. pratensis native to California?
No. Poa pratensis subsp. pratensis is not native to California (recorded as not native).
When does Poa pratensis subsp. pratensis bloom?
Poa pratensis subsp. pratensis blooms Mar-Jul.
What plant family does Poa pratensis subsp. pratensis belong to?
Poa pratensis subsp. pratensis is in the Poaceae family, genus Poa.
Is Poa pratensis subsp. pratensis invasive in California?
Poa pratensis subsp. pratensis is listed by Cal-IPC with an invasiveness rating of Yes.
What habitat does Poa pratensis subsp. pratensis grow in?
Poa pratensis subsp. pratensis grows in Common. Disturbed habitats, pastures, tolerating sub-saline and sub-alkaline soils.
Related species
Other California species in the same genus, family, or bioregion.
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.