Poa compressa
Canadian blue grass
(c) Matt Lavin, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Grass · Not Native
Poa compressa (Canadian blue grass) is a non-native California grass in the Poaceae family, recognized by flattened stems and bent nodes.
Canadian blue grass is a naturalized perennial grass found in California in moist, often disturbed low ground at elevations below 2,000 meters. Flowering from April to August, this grass produces small, compact flower clusters in dense lanceolate panicles. Growing with distinctively flattened and keeled stems 15 to 60 centimeters tall, it spreads through long, stout rhizomes with nodes that are noticeably exposed and lower nodes that are abruptly bent. Its leaf blades are 1.5 to 4 millimeters wide, soft to somewhat firm, and can be flat or folded, with open sheaths and rounded ligules. The grass has delicate spikelets with lemmas 2.3 to 3.5 millimeters long, featuring hairy marginal veins and keels.
Identification and appearance
Key characters: 47 sympatric species; diagnostic flattened stems and bent nodes
Habitat and range
Habitat: Moist, often disturbed low ground
Elevation: < 2000 m
Outside California: +- worldwide temperate; native to Europe.
Bloom period
Poa compressa blooms Apr-Aug.
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 compressa native to California?
No. Poa compressa is not native to California (recorded as not native).
When does Poa compressa bloom?
Poa compressa blooms Apr-Aug.
What plant family does Poa compressa belong to?
Poa compressa is in the Poaceae family, genus Poa.
What habitat does Poa compressa grow in?
Poa compressa grows in Moist, often disturbed low ground.
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.