Poa trivialis - L.
Scribner's Bluegrass
Other English Common Names: Rough Bluegrass, Rough-stalked Bluegrass
Other Common Names: rough bluegrass
Taxonomic Status: Accepted
Related ITIS Name(s): Poa trivialis L. (TSN 41163)
Unique Identifier: ELEMENT_GLOBAL.2.137402
Element Code: PMPOA4Z2H0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Poa
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Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Poa trivialis
Conservation Status

NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (19Sep2016)

U.S. & Canada State/Province Status
United States Alabama (SNA), Alaska (SNA), California (SNA), Colorado (SNA), Connecticut (SNA), Delaware (SNA), District of Columbia (SNA), Georgia (SNR), Idaho (SNA), Illinois (SNA), Indiana (SNA), Iowa (SNA), Kansas (SNA), Kentucky (SNA), Louisiana (SNR), Maine (SNA), Maryland (SNA), Massachusetts (SNR), Michigan (SNA), Minnesota (SNA), Missouri (SNA), Nebraska (SNA), Nevada (SNA), New Hampshire (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), North Carolina (SNA), Ohio (SNA), Oregon (SNA), Pennsylvania (SNA), Rhode Island (SNA), South Dakota (SNA), Tennessee (SNA), Utah (SNA), Vermont (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wisconsin (SNA), Wyoming (SNA)
Canada Alberta (SNA), British Columbia (SNA), New Brunswick (SNA), Newfoundland Island (SNR), Nova Scotia (SNA), Ontario (SNA), Prince Edward Island (SNA), Quebec (SNA), Yukon Territory (SNR)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States AKexotic, ALexotic, CAexotic, COexotic, CTexotic, DCexotic, DEexotic, GA, IAexotic, IDexotic, ILexotic, INexotic, KSexotic, KYexotic, LA, MA, MDexotic, MEexotic, MIexotic, MNexotic, MOexotic, NCexotic, NEexotic, NHexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, ORexotic, PAexotic, RIexotic, SDexotic, TNexotic, UTexotic, VAexotic, VTexotic, WAexotic, WIexotic, WVexotic, WYexotic
Canada ABexotic, BCexotic, NBexotic, NF, NSexotic, ONexotic, PEexotic, QCexotic, YT

Range Map
No map available.

Ecology & Life History Not yet assessed
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank)
Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: Medium/Low
Rounded I-Rank: Medium
I-Rank Reasons Summary: This is a widespread weed of lawns/turfs and moist disturbed areas with little documentation of serious impacts to native species and ecosystems. It could easily be I-ranked 'Low' but there is some indication that it may be somewhat overlooked in terms of its impacts---or at least its presence--- in higher quality habitats, especially in portions of the eastern U.S. At this time, the calculated I-rank of Medium/Low seems appropriate.
Subrank I - Ecological Impact: Low/Insignificant
Subrank II - Current Distribution/Abundance: High
Subrank III - Trend in Distribution/Abundance: Medium/Low
Subrank IV - Management Difficulty: High/Low
I-Rank Review Date: 28Jun2006
Evaluator: K. Maybury
Native anywhere in the U.S?
Native Range: Europe (Hitchcock 1951).

Download "An Invasive Species Assessment Protocol: Evaluating Non-Native Plants for their Impact on Biodiversity". (PDF, 1.03MB)
Provide feedback on the information presented in this assessment

Screening Questions

S-1. Established outside cultivation as a non-native? YES

S-2. Present in conservation areas or other native species habitat? Yes

Subrank I - Ecological Impact: Low/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance/Insignificant
Comments: No significant impacts reported. Lacks rhizomes and does not form sods as dense as does Poa pratensis, to which it is sometimes compared (Kemper Center, no date).

2. Impact on Ecological Community Structure:Low significance/Insignificant
Comments: No serious impacts reported. Lacks rhizomes and does not form sods as dense as does Poa pratensis, to which it is sometimes compared (Kemper Center, no date).

3. Impact on Ecological Community Composition:Medium significance/Insignificant
Comments: Unknown but presumed not high as bluegrasses rarely produce pure stands (Alaska Natural Heritage Program 2005) and no evidence of significant impacts were found in the literature consulted.

4. Impact on Individual Native Plant or Animal Species:Low significance/Insignificant
Comments: No disproportionate impacts noted.

5. Conservation Significance of the Communities and Native Species Threatened:Medium/Low significance
Comments: In many floras and other sources Poa trivialis is reported from disturbed areas, waste places, and lawns (e.g., Hulten 1968, Hickman 1993) and there is a large body of information regarding this species in terms of it being an undesirable component of turf grasses for golf courses, etc. However, this may obscure the fact that this species also appears to be impacting higher quality habitats, at least in some areas. Heffernan et al. (2001) noted that that it occurred in 20 of 1994 vegetation plots (1 percent of plots) in Virginia where plot selection had been deliberately biased toward pristine vegetation. Its relatively high frequency in these plots is "certainly a warning sign" (Heffernan, pers. comm., 2006).

Subrank II. Current Distribution and Abundance: High

6. Current Range Size in Nation:High significance
Comments: Naturalized throughout most of the U.S. with only Hawaii and a few southern states (and North Dakota) lacking confirmed reports (Kartesz 2006, unpublished data).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:High significance
Comments: Some negative impacts assumed in at least 20 percent or more of the U.S. distribution. Possibly most negative impacts are in the Mid-Atlantic and lower New England? It is noted as being common in the Southeast by Weakley (2006) but "very local" in Michigan (Voss 1985), "uncommon" in Maine (Haines and Vining 1998), and generally much more sporadically distributed elsewhere according to county distribution information (Kartesz, 2006 unpublished data).

8. Proportion of Nation's Biogeographic Units Invaded:High significance

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High significance
Comments: Moist places, both open and shaded including meadows/praries, open woodlands, moist forests, bottomlands, disturbed sites (Hitchcock 1951, Hulten 1968, Voss 1985, Hickman 1993, Weakley 2006).

Subrank III. Trend in Distribution and Abundance: Medium/Low

10. Current Trend in Total Range within Nation:Low significance
Comments: This species is already occuring nearly throughout the generalized range and is assumed to be stable.

11. Proportion of Potential Range Currently Occupied:Insignificant
Comments: Long planted (intentionally and unintentionally) as a turfgrass and now assumed to have occupied most of its potential range.

12. Long-distance Dispersal Potential within Nation:High significance
Comments: This is widely sold and planted in seed mixes as a turfgrass for golf courses and other grassy areas. It is also a common contaminate of commercial grass seed in general (Liskey 1999). Dispersal by humans aside, this grass does not appear to have obvious adaptations for long-distance dispersal (Alaska Natural Heritage Program 2005).

13. Local Range Expansion or Change in Abundance:Medium significance/Insignificant
Comments: Unknown but presumed not expanding extremely rapidly.

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Medium/Low significance
Comments: Requires light to germinate (Froud-Williams and Ferris 1987 as cited in Alaska Natural Heritage Program 2005) and appears to require some level of substrate disturbance for successful invasion (Alaska Natural Heritage Program 2005).

15. Similar Habitats Invaded Elsewhere:Low significance
Comments: Naturalized in Australia (Weiller et al. 1995) and Canada (Kartesz 1999) but presumably in similar habitats.

16. Reproductive Characteristics:Low significance
Comments: Can produce over 1000 seeds per plant (Froud-Willaims and Ferris 1987 as cited in Alaska Natural Heritage Program 2005) but lacks the potential for aggressive spread by rhizomes that Poa pratensis has.

Subrank IV. General Management Difficulty: High/Low

17. General Management Difficulty:High/Low significance
Comments: Unknown but assumed not insignficant.

18. Minimum Time Commitment:High/Low significance
Comments: Unknown but assumed not insignficant.

19. Impacts of Management on Native Species:High/Moderate significance
Comments: Most information on reducing or controlling this species is directed at lawn and turf situations were the only options are non-selective herbicides that kill all associated species as well (Liskey 1999). Presumably, in native grassland/forb situations a similar lack of options would exist. In other natural situations, control without damage to native species may be much easier.

20. Accessibility of Invaded Areas:High significance
Comments: Widely planted on private lands.

Other Considerations: Additional information regarding impacts in natural habitats would be very useful.

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Alaska Natural Heritage Program. 2005. Non-native plant species of Alaska: Kentucky bluegrass (Poa pratensis ssp. pratensis L.), spreading bluegrass (Poa pratensis ssp. irrigata (Lindm.) Lindb. f.), rough bluegrass (Poa trivialis). Last updated October 13, 2005. Online: http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_POPR&POTR.pdf. Accessed 2006.

  • C.M. Weiller, M.J. Henwood, J. Lenz and L. Watson. 1995. Pooideae (Poaceae) in Australia - Descriptions and Illustrations. Online: http://muse.bio.cornell.edu/delta/ . Accessed 2006.

  • Dore, W.G. and J. McNeill. 1980. Grasses of Ontario. Monograph 26, Agriculture Canada, Research Branch, Biosystematics Research Institute, Ottawa, Ontario. 566 pp.

  • Haines, A. and T.F. Vining. 1998. Flora of Maine, A Manual for Identification of Native and Naturalized Vascular Plants of Maine. V.F.Thomas Co., Bar Harbor, Maine.

  • Heffernan, K. E., P. P. Coulling, J. F. Townsend, and C. J. Hutto. 2001. Ranking invasive exotic plants species in Virginia. Natural Heritage Technical Report 01-13. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, Virginia.

  • Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.

  • Hitchcock, A.S. 1951. Manual of the grasses of the United States. 2nd edition revised by Agnes Chase. [Reprinted, 1971, in 2 vols., by Dover Publications, Incorporated, New York.]

  • Hulten, E. 1968. Flora of Alaska and neighboring territories. Stanford Univ. Press, Palo Alto, CA. 1008 pp.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.

  • Kemper Center for Home Gardening. No date. PlantFinder. Missouri Botanical Garden. Online:: http://www.mobot.org/gardeninghelp/plantfinder/serviceplantfinder.shtml

  • Liskey, E. 1999. Poa trivialis: Friend and foe. Grounds Maintenance. April 1, 1999. Online: http://grounds-mag.com/mag/grounds_maintenance_poa_trivialis_friend/index.html. Accessed 2006.

  • Meades, S.J. & Hay, S.G; Brouillet, L. 2000. Annotated Checklist of Vascular Plants of Newfoundland and Labrador. Memorial University Botanical Gardens, St John's NF. 237pp.

  • Voss, E.G. 1985. Michigan flora. Part II. Dicotyledons. Cranbrook Institute of Science and University of Michigan Herbarium. Ann Arbor, Michigan. 1212 pp.

  • Weakley, A. S. 2006. Flora of the Carolinas, Virginia, Georgia, and surrounding areas. Working draft of 17 January 2006. University of North Carolina Herbarium, North Carolina Botanical Garden, Chapel Hill. Online. Available: http://www.herbarium.unc.edu/flora.htm (accessed 2006).

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