Poa nemoralis
(wood bluegrass)

Preferred Common Name

• wood bluegrass

Other Scientific Names

• Agrostis alba L.
• Agrostis stolonifera f. alba (L.) Schur
• Agrostis vulgaris var. alba (L.) Gatt.
• Aira elodes Brign.
• Catabrosa elodes (Brign.) Roem. & Schult.
• Catabrosa helodes Roem. & Schult.
• Decandolia alba (L.) T. Bastard
• Eragrostis tenuis Steud.
• Festuca capitata Balb. ex Spreng.
• Festuca depauperata Bertol.
• Milium album (L.) Lag.
• Paneion nemorale (L.) Lunell
• Paneion nemorale L.
• Poa acmocalyx Keng f. & L.Liu
• Poa adjarica (Sommier & Levier) A.P.Khokhr.
• Poa alexeenkoi (Tzvelev) Czerep.
• Poa angustifolia var. nemoralis (L.) Huds.
• Poa asperula Steud.
• Poa balbisii Parl.
• Poa balfourii auct.
• Poa balfourii auct.
• Poa caespitosa Poir.
• Poa cinerea Vill.
• Poa coarctata Haller f. ex Gaudich.
• Poa debilis Thuill.
• Poa firmula (Gaudich.) Gray
• Poa glauca subsp. glaucantha (Gaudich.) Lindm.
• Poa glaucantha Schleich. ex Gaudin
• Poa glaucescens Roth
• Poa gracilescens Schrad.
• Poa hypanica Prokudin
• Poa juncea Suter
• Poa juncoides Gaudich.
• Poa korshunensis Golosk.
• Poa lapponica Prokudin
• Poa muralis Honck.
• Poa parnellii Bab.
• Poa pilipes Keng f. ex Shan Chen
• Poa polymorpha Wibel
• Poa pratensis var. cinerea (Vill.) Mathieu
• Poa pratensis var. fagetorum Rech. & T.C.Scheff.
• Poa scheuchzeri Suter
• Poa scopulorum Butters & Abbe
• Poa subpolaris Kuvaev
• Poa tenuis Clairv.
• Vilfa alba (L.) P.Beauv.

International Common Names

• English: woodland bluegrass

Local Common Names

• Canada: foin à vaches; forest bluegrass; pâturin des bois; woods bluegrass
• China: lin di zao shu he
• France: pâturin des bois
• Germany: Hainrispengras
• Italy: fienarola dei boschi
• Japan: tachi-ichigo-tsunagi
• Korea, Republic of: seonpoapul
• Russian Federation: mjatlik lesnoj
• Sweden: lundgröe
• UK: wood meadow grass
• USA: inland bluegrass

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Monocotyledonae
•                     Order: Cyperales
•                         Family: Poaceae
•                             Genus: Poa
•                                 Species: Poa nemoralis

Poa nemoralis L. is a grass species from the family Poaceae. Poa is Greek for fodder and nemoralis is Latin for growing in the woods. Hence its common name wood bluegrass. The Plant List (2013) lists 104 synonyms for this species.

In the PLANTS Database (USDA-NRCS, 2016) two subspecies are documented:  inland bluegrass (P. nemoralis  subsp. interior (Rydb.) W.A. Weber) which is considered native to North America, and wood bluegrass (P. nemoralis  subsp. nemoralis) which is introduced. However, this datasheet follows other treatments that accept P. interior Rydb. as a separate valid species (e.g. The Plant List, 2013).

There has been much debate over the boundary between mountain forms of P. nemoralis and non-glaucous forms of Poa glauca Vahl.. The form sometimes known as Poa balfourii Parn. is now included in P. glauca, not in P. nemoralis (Farmer, 2004).

The following description is from Utah State University (2016):

Plants perennial; green or glaucous; densely tufted, not stoloniferous, not rhizomatous. Basal branching all or mostly extravaginal.

Culms 30-80 cm, mostly erect, smooth below the panicles; nodes slightly com-pressed, 2-5 exserted, top node at 1/2-3/4 the culm length.

Sheaths closed for 1/10-1/5 their length, terete, bases of basal sheaths glabrous, distal sheath lengths 0.45-1 (1.1) times blade lengths; ligules 0.2-0.8(1) mm, sparsely to densely scabrous, apices truncate, minutely ciliolate; blades 0.8-3 mm wide, mostly flat, appressed, abruptly ascending to spreading, straight or somewhat lax, apices narrowly prow-shaped.

Panicles 7-16(20) cm, lengths usually 2.5-4 times widths at maturity, usually erect, lax in shade forms, narrowly lanceoloid to ovoid, slightly to moderately congested; nodes with 2-5 b-anches; branches ascending to widely spreading, fairly straight, slender to moderately stout, angled, angles moderately to densely scabrous.

Spikelets 3-8 mm, lengths 2.5-3.5 times widths, narrowly lanceolate to lanceolate, laterally compressed, usually not glaucous; florets (1)2-5; rachilla internodes usually shorter than 1 mm, smooth, muriculate, or scabrous, usually puberulent, infrequently hispidulous or glabrous.

Glumes subulate to narrowly lanceolate, distinctly keeled, keels smooth or sparsely scabrous, apices sharply acute to acuminate; lower glumes 3-veined, long-tapered to a slender point, lengths 6.4-11 times widths; upper glumes shorter than or subequal to the lowest lemmas; calluses webbed, hairs sparse, often short; lemmas 2.4-4 mm, proximal lemma widths less than 1/5 times lengths, narrowly lanceolate to lanceolate, distinctly keeled, keels and marginal veins short-villous, lateral veins glabrous, obscure, intercostal regions smooth or muriculate, glabrous, margins glabrous, apices acute, usually partially bronze-colored; palea keels scabrous, intercostal regions glabrous; anthers 0.8-1.9 mm. Caryopses 1.5 mm long.

A description of P. nemoralis, along with photographs, is also given by Lind (2013).

Introduced from Eurasia, it is now common in mixed woodlands of the northeastern United States and is spreading to the West (New England Wild Flower Society, 2016; Utah State University, 2016). Although an exact date of introduction cannot be found in Clark and Malte (1913) it is stated that seeds of P. nemoralis were mainly obtained from Germany.

Soil texture

• medium

Natural Dispersal

P. nemoralis produces seeds asexually (apomixis) which facilitates its spread, particularly long-distance (Asker and Jerling, 1992; Poschlod et al., 2003) (for more detailed information on apomixis in P. nemoralis see Naumova et al. (1999)). It can also reproduce vegetatively (another type of asexual reproduction) which facilitates more local spread (Asker and Jerling, 1992).

Accidental Introduction

Possibly introduced with wool shoddy, grass-seed or soil (Online Atlas of the British and Irish Flora, 2016).

Intentional Introduction

Introduced to provide grass cover (see Uses section).

A study by Dibble and Rees (2005) suggests that non-native plants have altered fuel characteristics in coniferous forests in southern Maine, USA; grasses such as P. nemoralis contribute to the fine-fuel load and may extend the period of fire threat under drought conditions.  

P. nemoralis is reported to be capable of becoming invasive in some forests in Wisconsin, USA (University of Wisconsin, 2016).

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Is a habitat generalist
• Pioneering in disturbed areas
• Tolerant of shade
• Has propagules that can remain viable for more than one year
• Reproduces asexually

• Modification of fire regime
• Threat to/ loss of native species

• Competition (unspecified)

• Difficult to identify/detect as a commodity contaminant

Economic Value

Sown in woodlands, parks, gardens and playing fields due to its ornamental value as a lawn or turfgrass (Watson and Dallwitz, 1992; Online Atlas of the British and Irish Flora, 2016).