Phleum pratense - L.
Meadow Timothy
Other English Common Names: Timothy
Other Common Names: timothy
Taxonomic Status: Accepted
Related ITIS Name(s): Phleum pratense L. (TSN 41062)
French Common Names: fléole des prés
Unique Identifier: ELEMENT_GLOBAL.2.135574
Element Code: PMPOA4U050
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Phleum
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Concept Reference
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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: Phleum pratense
Conservation Status
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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 (07Mar2016)

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

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

Distribution
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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, ARexotic, AZexotic, CAexotic, COexotic, CTexotic, DCexotic, DEexotic, GA, HIexotic, IAexotic, IDexotic, ILexotic, INexotic, KSexotic, KYexotic, LAexotic, MA, MDexotic, MEexotic, MIexotic, MNexotic, MOexotic, MSexotic, MTexotic, NCexotic, NDexotic, NEexotic, NHexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, OKexotic, ORexotic, PAexotic, RIexotic, SCexotic, SDexotic, TNexotic, TXexotic, UTexotic, VAexotic, VTexotic, WAexotic, WIexotic, WVexotic, WYexotic
Canada ABexotic, BCexotic, LBexotic, MBexotic, NBexotic, NFexotic, NSexotic, NTexotic, NUexotic, ONexotic, PEexotic, QCexotic, SKexotic, YTexotic

Range Map
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Ecology & Life History Not yet assessed
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Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank)
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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
Rounded I-Rank: Medium
I-Rank Reasons Summary: This species can cause declines in and competitively exclude native grasses and may occur in national and state park areas. It currently occurs in every U.S. state and is considered noxious in many. Because it is so widespread and common, continued invasive potential is only local within existing range. The species is capable of invading early- to mid-successional grasslands and early-seral mixed forests. Seeds are easily dispersed by wind and have spread widely via agriculture. Various control measures have met with moderate success although control in areas of conservation concern is difficult as most control methods negatively affect native species.
Subrank I - Ecological Impact: Medium/Low
Subrank II - Current Distribution/Abundance: High
Subrank III - Trend in Distribution/Abundance: Medium
Subrank IV - Management Difficulty: Medium
I-Rank Review Date: 27Jun2006
Evaluator: J. Cordeiro, rev. K. Gravuer
Native anywhere in the U.S?
Native Range: Timothy is Eurasian in origin but was first cultivated in the United States and was found growing as an invasive in New England in the 1700s (Hoover et al., 1948).

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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: This species has become naturalized as a non-native throughout most of the United States and southern Canada (Uva et al., 1997).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: This species was once widely used for hay production and has hence been spread widely via agriculture in the U.S. (Hitchcock, 1951).

Subrank I - Ecological Impact: Medium/Low

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance
Comments: Because of the vast invasive potential of this species and because it comes to dominate areas it invades, it is assumed that some negative impacts on ecosystem processes are present.

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: Timothy often dominates the area it occupies (Weaver et al., 1990). This species has been found to decrease both cover and diversity of native species in various national parks in the U.S. (Tyser, 1992; Tyser and Worley, 1992).

3. Impact on Ecological Community Composition:Moderate significance
Comments: Timothy often dominates the area it occupies (Weaver et al., 1990). This species has been found to decrease both cover and diversity of native species in various national parks in the U.S. (Tyser, 1992; Tyser and Worley, 1992). Timothy seedlings can be detrimental or beneficial in young conifer plantations. They may hinder conifer seedling establishment by preemption of resources, allelopathy, attraction of insects and animals, and increased fire potential. They can be beneficial by excluding other competitive plant species. Timothy seedlings compete strongly with conifer seedlings, especially when conifer seedlings are not fully established. After establishment of conifer seedlings, approximately 5 years, timothy seeds may aid conifer seedling growth by excluding shrub competition (McDonald, 1986).

4. Impact on Individual Native Plant or Animal Species:Low significance/Insignificant
Comments: Little evidence of disproportionate impacts on particular native species was found in the literature. However, timothy competes successfully with native grasses where moisture and soil are favorable (Sampson et al., 1951). Phleum pratense also appears to exclude other grass species in abandoned pastures (> 20 years after abandonment) in Japan through interspecific competition (Tsuyuzake and Kanda, 1996). Similarly, this species has been found to decrease both cover and diversity of native species in various national parks in the U.S. (Tyser and Worley, 1992; Tyser, 1992). Murphy and Aarssen (1989; 1995a) found that pollen extract from P. pratense drastically reduced pollen germination in 37 (of 40 tested) other species with germination count falling to zero for some species tested. Similarly, Murphy and Aarssen (1995b) found that P. pratense pollen extract also decreased mean seed set in sympatric grassland species, as well.

5. Conservation Significance of the Communities and Native Species Threatened:High/Moderate significance
Comments: Exotic grasses are one of the most disruptive factors in native fescue grasslands in Glacier National Park. Timothy is the most widely distributed exotic in the park, where it is associated with substrate disturbed by post-1980 underground utility construction. Timothy was intentionally seeded by outfitters in the 1940's and by park personnel in the 1980's. Extensive tiller mats of timothy limit cryptogam colonization sites and reduce native graminoid colonization (Tyser, 1992). Until about 1980, revegetation efforts in national parks (including Glacier National Park) commonly included seeding primary and secondary roadsides, with alien seed mixes of species such as Phleum pratense, and plants have successfully spread into backcountry areas of these parks away from roads (Tyser and Worley, 1992). Similar intentional plantings to feed horses and cows ware now well established and considered beyond control in other North American National Parks (e.g. Waterton Lakes National Park in Alberta, Canada; see Coleman, 1994). The species also occurs in other National Parks including Grand Canyon National Park, Indiana Dunes National Lakeshore, Pipestone National Monument, and Wind Caves National Park (APRS, 2001).

Subrank II. Current Distribution and Abundance: High

6. Current Range Size in Nation:High significance
Comments: Timothy is currently distributed in every U.S. state as well as much of southern Canada (USDA, 2006; NRCS, 2002).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:High/Moderate significance
Comments: This species is considered an invasive throughout the U.S. with negative impacts throughout its introduced range.

8. Proportion of Nation's Biogeographic Units Invaded:High significance
Comments: It is conservatively estimated that well over half of the 81 ecoregions have been invaded by Phleum pratense as it occurs in every U.S. state (Cordeiro, pers. obs. June 2006 based on TNC, 2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High/Moderate significance
Comments: Timothy is cultivated for hay but may occur as a weed of low-maintenance turfgrass, as well as nursery, orchard, agricultural and forage crops. It also grows in roadsides and abandoned fields but generally requires nutrient rich soils (Uva et al., 1997). Timothy has escaped cultivation and has become established at medium to high elevations in the mountains where it grows in moist grasslands, in aspen and conifer stands, and along roadways. It has become naturalized on sites ranging from warm, dry grasslands to cool, moist supalpine forests (Forcella and Harvey, 1983).

Subrank III. Trend in Distribution and Abundance: Medium

10. Current Trend in Total Range within Nation:Moderate significance
Comments: This species has expanded across the United States into every state and continues to expand within most states (Esser, 1993).

11. Proportion of Potential Range Currently Occupied:Insignificant
Comments: This species has expanded across the United States into every state and continues to expand within most states (Esser, 1993).

12. Long-distance Dispersal Potential within Nation:High significance
Comments: This species was once widely used for hay production and has hence been spread widely via agriculture (Hitchcock, 1951). It also spreads by seed into surrounding areas when used for reclamation. Until about 1980, revegetation efforts in national parks (including Glacier National Park) commonly included seeding primary and secondary roadsides, with alien seed mixes of species such as Phleum pratense, and plants have successfully spread into backcountry areas of these parks away from roads (Tyser and Worley, 1992; Tyser, 1992). It can also be spread by equine activities as well as activities of wild animals such as deer, mule deer, and mountain sheep (Esser, 1993; Hobbs et al., 1981; Hungerford, 1970). Timothy can be used with legumes and/or other grasses in a mix for cover purposes, filter strips, waterways, and other critical area applications (NRCS, 2002).

13. Local Range Expansion or Change in Abundance:Low significance
Comments: Since much of the United States has invasive occurrences of this species where it has reached nearly its fullest potential, local expansions are limited to select sites within states where the species has not yet been introduced.

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Moderate significance
Comments: Timothy usually occurs in early to mid seral stages, although it can also dominate in self-perpetuating grasslands. It is an intermediate competitor. It colonizes disturbed areas via seed. Timothy has been observed in early seral mixed forests (Esser, 1993). In southwest Ohio, it was found in fields up to 50 years of age but not in fields 90 years of age (Vankat and Carson, 1991). Timothy does better following disturbance of sites in early successional stages compared with those in later successional stages.

Timothy thrives best on rich, moist bottomlands and on finer textured soils, such as clay loams. It does not do well on coarser soils. It prefers a pH of 5.5 to 7.0. Timothy will grow for a time on soils low in fertility, but it is better adapted to a high fertility soil. It is not well adapted to wet, flat land where water stands for any considerable time, though it can withstand somewhat poorly-drained soils. Under limited moisture conditions, it makes a poor recovery and it does not tolerate drought or prolonged high temperatures (NRCS, 2002). Plants establish quickly, spread vigorously, and usually escape early detection. Timothy has the highest ability of 34 exotics tested to invade closed vegetation areas. Constancy values in forest, meadow, and alpine tundra is 99, 99, and 36 percent, respectively. Numbers and frequency of timothy increases from undisturbed sites to regularly disturbed sites. More resources are available at the latter sites because competition is greatly reduced. Taylor and Aarson (1990) found that this grass species had greater competetive abilities than two other invasive grass species, including Agropyron repens and Poa pratensis.


15. Similar Habitats Invaded Elsewhere:Low significance
Comments: Habitats invaded elsewhere are similar to in the U.S.

16. Reproductive Characteristics:High significance
Comments: Propagation is generally by seed and the root system is fibrous and predominates from short rhizomes and occasionally short stolons (Uva et al., 1997). It is a prolific seeder (vigorous and fast-growing) with maximum germination usually occuring about 3 or 4 weeks after it is harvested, when nearly 100 percent should germinate. Germination rates remain high for 1 to 2 years. Timothy seed remains viable for 4 to 5 years if kept in a dry, cool place (Esser, 1993). Timothy reproduces vegetatively through tillering. When timothy plants are plowed under, many become reestablished through rooting stems which develop and grow upwards to the surface. Vegetative reproduction occurs through buds in the axils of the leaves, at nodes which may or may not be adjacent to the corms (Anderson et al., 1989). The species is relatively short-lived, however (NRCS, 2002). Seed banking capability is also high for this species (Tsuyuzaki and Kanda, 1996).

Subrank IV. General Management Difficulty: Medium

17. General Management Difficulty:Moderate significance
Comments: Control should include both elimination and simultaneous introduction of a desirable competitor (Weaver et al., 1990). Fire has also been shown to reduce flowering and yield (Richards and Landers, 1973). Moderately severe fires will top-kill timothy, and severe fires may cause damage to or kill the root crown, killing the plant (Anderson and Romme, 1991). However, fire stimulates the production of reproductive tillers in timothy (Esser, 1993; Cornely et al., 1983; Ehrenreich and Aikman, 1963).

18. Minimum Time Commitment:Medium/Low significance
Comments: In a study of revegetation patterns in abandoned pastures in northern Japan, Tsuyuzake and Kanda (1996) found that introduced grasses including Phleum pratense, were abundant even > 20 years after pasture abandonment, indicating these exotic species could persist and affect revegetation for a few decades. When a single spring (mid-April) headfire under moist litter conditions was applied to an Iowa tallgrass prairie site flowering was significantly inhibited for creeping bentgrass (Agrostis stolonifera) and timothy (Phleum pratense) (Richards and Landers, 1973).

19. Impacts of Management on Native Species:High/Moderate significance
Comments: Reduction of timothy is not a realistic option in Glacier or other natural areas; the most reasonable recommendation for resource managers is not to use it for revegetating disturbed sites (Tyser, 1992). Grasses should be eliminated from plantations until conifer seedlings have become established; the limiting resource is soil moisture (McDonald, 1986).

20. Accessibility of Invaded Areas:Low significance/Insignificant
Comments: It appears most to all areas are easily accessible. Access to private lands may be an issue where this species is deliberately planted.
Authors/Contributors
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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).

References
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  • Anderson, J.E. and W.H. Romme. 1991. Initial floristics in lodgepole pine (Pinus contorta) forests following the 1988 Yellowstone fires. International Journal of Wildland Fire, 1(2): 119-124.

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  • Murphy, S.D. and L.W. Aarssen. 1995. Alleopathic pollen extract from Phleum pratense L. (Poaceae) reduces germination, in vitro, of pollen of sympatric species. International Journal of Plant Sciences, 156(4): 425-434.

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