Poa bulbosa
Bulbous blue grass
(c) Tom Norton, some rights reserved (CC BY), uploaded by Tom Norton · licence
Family: Poaceae · Type: Grass · Not Native
Poa bulbosa (Bulbous blue grass) is a non-native California grass in the Poaceae family, recognized by Naturalized Poa; swollen bulb-like stem base — nearly diagnostic among CA bluegrasses.
Bulbous blue grass is a naturalized perennial grass found in disturbed areas at low elevations. Flowering in spring, this grass produces small, delicate green to light brown flower clusters in compact formations. Growing densely in clumps with distinctively bulbous bases, the grass reaches 15 to 60 centimeters tall with soft, slender stems. Its narrow leaves are 1 to 2 millimeters wide, soft and flat or slightly folded, quickly withering after emerging. The plant is characterized by its unique vegetative reproduction, forming small bulblets in its spikelets alongside normal flowers.
Identification and appearance
Key characters: Naturalized Poa; swollen bulb-like stem base — nearly diagnostic among CA bluegrasses
Habitat and range
California counties: Kern, San Luis Obispo, Riverside, Tehama, Lassen, Plumas, Santa Barbara, Modoc, Tulare, Humboldt, Tuolumne, Fresno, Del Norte, Lake, El Dorado, San Diego, Shasta, Santa Clara, Trinity, San Bernardino, Madera, Siskiyou, Los Angeles, Ventura, Yolo, Calaveras, Sierra, Sacramento, Nevada, Amador, Placer, Mono, Colusa, Sonoma, Contra Costa, Alameda, Imperial, Mendocino, Napa, San Benito, San Mateo, Sutter, Butte, Marin, Mariposa, San Joaquin, Glenn, Merced, Alpine, Inyo, Monterey, Solano, Stanislaus
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 bulbosa native to California?
No. Poa bulbosa is not native to California (recorded as not native).
Where in California does Poa bulbosa grow?
Poa bulbosa occurs in Kern, San Luis Obispo, Riverside, Tehama, Lassen, Plumas, Santa Barbara, Modoc and other counties.
What plant family does Poa bulbosa belong to?
Poa bulbosa is in the Poaceae family, genus Poa.
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.