Ventenata dubia
(North Africa grass)

Preferred Scientific Name

• Ventenata dubia (Leers) Coss. & Durieu

Preferred Common Name

• North Africa grass

Other Scientific Names

• Avena dubia Leers
• Avena fertilis All.
• Avena triaristata Vill.
• Festuca tenuis (Moench) Raspail
• Gaudinia tenuis (Moench) Trin.
• Heteranthus dubius (Leers) Thell.
• Heteranthus tenuis (Moench) Dumort.
• Trisetaria tenuis (Host) Baumg.
• Trisetum tenue (Moench) Roem. & Schult.
• Ventenata avenacea Koeler
• Ventenata bromoides Koeler

International Common Names

• English: hairgrass; North Africa grass; softbearded oat grass; wiregrass
• French: venténata fausse-avoine; venténate douteuse; venténatée douteuse

Local Common Names

• Germany: Schmielenhafer

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

The genus name, Ventenata, is associated with French botanist Pierre Ventenat (1757-1805) (Nature Conservancy, 2000). The genus was previously placed within the Avena genus (subtribe Aveninae) and resides within the subtribe Airinae.

There are eight species in the genus Ventenata (The Plant List, 2013): V. blanchei Boiss., V. dubia (Leers) Coss. & Durieu, V. eigiana (H. Scholz & Raus) Dogan, V. huber-morathii (Dogan) D. Heller, V. macra (Steven) Balansa ex Boiss., V. quercetorum Boiss. & Bal., V. sorgerae (Dogan) D. Heller, and V. subenervis Boiss. & Balansa.

V. dubia is often referred to as wiregrass because its hardened stems can become tangled around the swather of a mowing machine (Scheinost et al., 2008).

V. dubia is a tufted winter annual grass with shallow fibrous roots. The stem is erect, 1.5-7 dm, and appears smooth, although tiny hairs can be seen when magnified. The leaf ligule is 1-6 mm long and the blade is 1-3 mm wide. Inflorescences are tawny to pale yellow, open, panicle-like, 3-10 cm long. The branches often spread until they droop. Spikelets (10-15 mm long) are near the branch tips and are stalked. The glumes are lancelolate, and end in a sharp tip. The lemmas have bent awns arising from their backs, much like those of wild oats (Avena barbata, A. fatua). The upper 1-2 florets are bisexual. Adapted from Nature Conservancy (2000) and Hitchcock (1969).

Soil drainage

• free
• impeded
• seasonally waterlogged

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Special soil tolerances

• shallow

Accidental Introduction

Within western North America, the primary pattern for dispersal is along roadways and trails (Lass and Prather, 2007). Dispersal likely is on vehicles since seeds are small and the pattern of dispersal is from road edge to adjacent lands (T Prather, University of Idaho, USA, personal communication, 2015).

Often the first places V. dubia is found is within areas that are saturated with water, typically because of an underlying restricted infiltration layer, for part of the spring (Anicito, 2013). V. dubia has been found as a contaminant in both hay fields and in grass fields grown for seed (Old and Callihan, 1987).

The long awns on its seed allow it to be spread by becoming attached to animals (Sheinost et al., 2008) and potentially vehicles and machinery.

In inland northwestern USA, V. dubia has resulted in the reduction of both grass hay production and grass stand life by as much as 50% and foreign export of infested hay is not possible. Overall yields are 20% lower because of V. dubia. Therefore farmers have had to change their practices and are trying various methods of control. Regional losses (in eastern Washington and northern Idaho, USA) are $6.7 million and ripple effects in the economy pose a $22 million negative impact (Prather, 2014).

V. dubia has a shallow root system which may make soil more susceptible to erosion. Its invasion leads to a decline in productivity and land value (Sheinost, 2008).

In Canada and the lower 48 states of the USA, V. dubia is considered a weed (Whitson et al., 1996).

Impact on Biodiversity

V. dubia changed plant species composition within Conservation Reserve Program lands (CRP - a land conservation programme administered by the Farming Service Agency) when it made up more than 50% foliar cover. The plant community change then resulted in changes to insect abundance during the nesting period of swallows that were foraging within CRP. Furthermore, reproduction of tree swallows was lower in areas with more than 50% foliar cover of V. dubia compared to areas with less than 10% foliar cover of V. dubia (Mackey, 2014).

Within its current distribution in northern Idaho and eastern Washington, USA, V. dubia has largely replaced cheatgrass (Bromus tectorum) as the dominant annual grass. In Oregon, where distribution overlaps with medusahead (Taeniatherum caput-medusae), V. dubia has become the dominant plant in many instances.

• Proved invasive outside its native range
• Highly adaptable to different environments
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Tolerant of shade
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Has propagules that can remain viable for more than one year

• Altered trophic level
• Changed gene pool/ selective loss of genotypes
• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Monoculture formation
• Negatively impacts agriculture
• Negatively impacts cultural/traditional practices
• Negatively impacts forestry
• Negatively impacts animal health
• Negatively impacts livelihoods
• Reduced amenity values
• Reduced native biodiversity
• Threat to/ loss of endangered species
• Threat to/ loss of native species
• Damages animal/plant products

• Antagonistic (micro-organisms)
• Competition - monopolizing resources
• Competition - shading
• Pest and disease transmission
• Herbivory/grazing/browsing
• Interaction with other invasive species

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field

Economic Value

V. dubia has little value as a forage plant since it becomes unpalatable to livestock once the stems harden after the panicles begin to emerge (Sheinost et al., 2008).