Anthoxanthum odoratum (sweet vernal grass)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Animals
- List of Symptoms/Signs
- Biology and Ecology
- Soil Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Anthoxanthum odoratum L.
Preferred Common Name
- sweet vernal grass
International Common Names
- English: buffalo grass; holy grass; large sweet vernal grass; scented vernal grass; sweet vernalgrass; sweet-scent vernal grass; vanilla grass
- Spanish: alesta olorosa; grama de olor; Pasto oloroso
- French: flouve odorante; foin d'odeu
- Chinese: huang hua mao; xiang huang hua mao
- Portuguese: feno-de-cheiro
Local Common Names
- Germany: Gemeines Ruchgras; Gewohnliches Ruchgras; Ruchgras; Wohlriechendes Ruchgras
- Italy: Paglietta odorata; Paleino odoroso; paleo odoroso
- Japan: harugaya
- Netherlands: Reukgras
- Sweden: vårbrodd
- AOXOD (Anthoxanthum odoratum)
Summary of InvasivenessTop of page
Anthoxanthum odoratum is a perennial grass of Eurasian origin that has been introduced to much of North America and Australia, and a number of other countries. It is presumed to have been introduced by European emigrants in the 18th and 19th centuries, both accidentally and as a pasture plant (although it is now not highly regarded for this purpose). It produces large numbers of seeds which can remain viable for several years, and tolerates a wide range of conditions. It can be a weed of pastures and natural habitats; in parts of Australia it is a threat to some endangered native species. It contains coumarins which in some plant species can be toxic to livestock, and it is listed as a cause of such toxicity, but it is also reported that the concentrations of these compounds are too low to cause problems.
PIER (2013) assessed this species as ‘High Risk’ for Hawaii, because of its rapid spread elsewhere, high seed production and possible toxicity to stock. Cal-IPC (2004) assess it as a Moderate threat to natural habitats in California.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Cyperales
- Family: Poaceae
- Genus: Anthoxanthum
- Species: Anthoxanthum odoratum
Notes on Taxonomy and NomenclatureTop of page
The Plant List (2010) lists 17 recognised species of Anthoxanthum; between them they are found throughout the world although most species are of limited distribution.
ITIS (2013) lists 10 subspecies and varieties of A. odoratum, but only two are listed as ‘accepted’: Anthoxanthum odoratum ssp. nipponicum (Honda) Tzvelev and Anthoxanthum odoratum ssp. odoratum L..
A related annual species, A. aristatum, originally from the Mediterranean, North Africa and Western Asia, is now naturalized in the United States, Australia, and elsewhere, but is not so widespread as A. odoratum and does not seem to pose so many problems. (See ‘Similarities to Other Species/Conditions’ section).
DescriptionTop of page
(Modified from Clayton et al., 2013)
Habit Perennial; caespitose. Butt sheaths papery; withering. Culms erect, or geniculately ascending; 10–75(–100) cm long; 1–3 -noded. Lateral branches lacking. Leaves mostly basal. Ligule an eciliate membrane; 1–5(–7) mm long. Leaf-blades 1–12(–30) cm long; 1.5–5(–9) mm wide; aromatic. Leaf-blade surface glabrous, or pubescent; hairy on both sides. Leaf-blade apex acuminate.
Inflorescence a panicle. Panicle spiciform; oblong, or ovate; continuous, or interrupted; 1–12 cm long; 0.6–1.5 cm wide. Spikelets solitary. Fertile spikelets pedicelled. Pedicels oblong; 0.5–1 mm long; pubescent.
Fertile spikelets comprising 2 basal sterile florets; 1 fertile floret; without rhachilla extension. Spikelets lanceolate; laterally compressed; 7–9.5 mm long; breaking up at maturity; disarticulating below each fertile floret.
Glumes persistent; dissimilar; exceeding apex of florets; thinner than fertile lemma; shiny. Lower glume ovate; 3.7–5.2 mm long; 0.5–0.6 x length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein smooth. Lower glume lateral veins absent. Lower glume surface pubescent. Lower glume apex acuminate. Upper glume elliptic; 7–9.5 mm long; 3–5 x length of adjacent fertile lemma; membranous; with hyaline margins; 1-keeled; 3 -veined. Upper glume primary vein smooth. Upper glume surface pubescent. Upper glume apex acuminate.
Florets Basal sterile florets dissimilar; barren; without significant palea; attached to and deciduous with the fertile. Lemma of lower sterile floret oblong; 2.8–3.6 mm long; 1.5–2 x length of fertile lemma; membranous; without keels; 4–5 -veined; pilose; emarginate; awned. Awn of lower sterile floret dorsal; arising 0.6 of way up back of lemma; 2–4 mm long. Lemma of upper sterile floret oblong; 3–3.5 mm long; 1 length of lower sterile floret; membranous; pilose; emarginate; awned. Awn of upper sterile floret dorsal; arising 0.1–0.2 of way up back of lemma; geniculate; 6–9 mm long. Fertile lemma orbicular; 1.7–2.4 mm long; cartilaginous; shiny; without keel; 5 -veined. Lemma lateral veins obscure. Lemma margins convolute; covering most of palea. Lemma apex obtuse. Palea oblong; 1 length of lemma; 1-veined; without keels.
Flower Lodicules absent. Anthers 2; (2.9–)3.5–4.8(–5.5) mm long. Stigmas 2; protogynous; pubescent.
Fruit Caryopsis with adherent pericarp; ellipsoid; 2 mm long. Embryo 0.33 x length of caryopsis. Hilum punctiform.
Plant TypeTop of page Grass / sedge
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.Last updated: 10 Jan 2020
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|South Africa||Present||Introduced||USDA-ARS (2013)|
|Pakistan||Present||Missouri Botanical Garden (2013)||Baluchistan & N.W.F.P.|
|South Korea||Present||Native||USDA-ARS (2013)|
|Bosnia and Herzegovina||Present||Native||USDA-ARS (2013)|
|Faroe Islands||Present||Native||USDA-ARS (2013)|
|Russia||Present||CABI (Undated)||Present based on regional distribution.|
|-Eastern Siberia||Present||Native||USDA-ARS (2013)|
|-Southern Russia||Present||Native||USDA-ARS (2013)|
|-Western Siberia||Present||Native||USDA-ARS (2013)|
|-Balearic Islands||Present||Native||USDA-ARS (2013)|
|-Canary Islands||Present||Native||USDA-ARS (2013)|
|United Kingdom||Present||Native||USDA-ARS (2013)|
|Canada||Present||CABI (Undated)||Present based on regional distribution.|
|-British Columbia||Present||Introduced||Invasive||Allred and Barkworth (2006); USDA-NRCS (2013)|
|-New Brunswick||Present||Introduced||USDA-NRCS (2013)|
|-Newfoundland and Labrador||Present||Introduced||USDA-NRCS (2013)|
|-Nova Scotia||Present||Introduced||USDA-NRCS (2013)|
|-Prince Edward Island||Present||Introduced||USDA-NRCS (2013)|
|Saint Pierre and Miquelon||Present||Introduced||USDA-NRCS (2013)|
|United States||Present||Introduced||USDA-ARS (2013)|
|-District of Columbia||Present||Introduced||USDA-NRCS (2013)|
|-New Hampshire||Present||Introduced||USDA-NRCS (2013)|
|-New Jersey||Present||Introduced||USDA-NRCS (2013)|
|-New Mexico||Present||Introduced||USDA-NRCS (2013)|
|-New York||Present||Introduced||USDA-NRCS (2013)|
|-North Carolina||Present||Introduced||USDA-NRCS (2013)|
|-Oklahoma||Present, Few occurrences||Introduced||Buthod and Hoagland (2011)||Prairie hay meadow in McIntosh County in east-central Oklahoma and roadside ditch in Pushmataha County in southeastern Oklahoma|
|-Rhode Island||Present||Introduced||USDA-NRCS (2013)|
|-South Carolina||Present||Introduced||USDA-NRCS (2013)|
|-West Virginia||Present||Introduced||USDA-NRCS (2013)|
|-New South Wales||Present, Localized||Introduced||Invasive||University of Queensland (2013)||In eastern areas and Australian Capital Territory|
|-Queensland||Present, Few occurrences||Introduced||University of Queensland (2013)||South-eastern areas|
|-South Australia||Present, Localized||Introduced||University of Queensland (2013)||South-eastern areas|
|-Tasmania||Present, Widespread||Introduced||Invasive||University of Queensland (2013)|
|-Victoria||Present, Widespread||Introduced||Invasive||University of Queensland (2013)|
|-Western Australia||Present, Localized||Introduced||University of Queensland (2013)||South-western areas|
|New Zealand||Present||Introduced||Invasive||USDA-ARS (2013)|
|Norfolk Island||Present||Introduced||University of Queensland (2013)|
History of Introduction and SpreadTop of page
Grant and Antonovics (1978) suggested that A. odoratum colonized the USA from Europe in the late 18th century. The first record in Australia was in Tasmania in 1840 (Council of Heads of Australasian Herbaria, 2013). Along with many other invasive plant species, it was presumably carried to the Americas, Australia and elsewhere by migrants from Europe who travelled to these ‘new’ countries and took with them pasture seeds as well as hay and straw for their animals, straw-filled palliasses and straw and other vegetation as packing material for their belongings. In 1843 the Agricultural and Horticultural Society of Auckland (New Zealand) recommended the importation of A. odoratum as a grass for pastures and by 1870 this species was being sown (Esler, 1987). Lambrechtsen (1968) reported that he found a record of the species being grown in New Zealand in 1847 and that it then spread rapidly throughout the country.
Risk of IntroductionTop of page
A. odoratum has already been spread to many countries where it can grow successfully. It could still be accidentally or deliberately spread further within those countries and to other countries where it has not yet established, but modern phytosanitary precautions at borders should limit the chances of further spread to more countries.
HabitatTop of page
In the British Isles, to which A. odoratum is native, Hubbard (1984) describes it as occurring in a great variety of habitats, often very abundant, on heaths and moors, in hill country grassland, old pastures, meadows and open woodlands. He goes on to say that it occurs on a wide range of soils from sands to clays, and in both wet and dry places.
In North America, where it has been introduced, it grows in meadows, pastures, grassy beaches, old hay fields, waste places, and openings in coniferous forests (occasionally in dense shade) or as a weed in lawns. In southern British Columbia, it is rapidly invading the moss-covered bedrock coastal bluffs and will soon exclude many native species (Allred and Barkworth 2006). Pitcher and Russo (1988) say that it is commonly a weed of pastures, hay fields, roadsides, and ditch banks in the southeastern United States. In Hawaii it is reported as naturalised in pastures, disturbed areas in wet forest, and sometimes subalpine shrubland, at altitudes of 840-2,140 m. (Wagner et al., 1999, in PIER, 2013).
In China, where it is native, its habitat is described as ‘meadows, alpine steppe; 1400–2900 m.’ (eFloras, 2013).
In Australia, where it has been introduced, the University of Queensland (2013) describes the species as commonly a weed of pastures, roadsides, disturbed sites and waste areas in temperate regions of the country. It also invades coastal environs, heathlands, heathy woodlands, grasslands, open woodlands, moist forests, temperate rainforest margins, riparian vegetation, freshwater wetlands, and alpine and sub-alpine vegetation; it is most invasive in moist or low fertility soils in sunny or semi-shaded sites. In New Zealand, too, it is widely distributed on roadsides, waste land, pasture and tussock grassland, in scrub or forest clearings, sometimes in boggy or sandy or rocky, stony ground, from sea level to alpine areas (Edgar and Connor, 2000).
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Secondary/tolerated habitat||Natural|
|Managed grasslands (grazing systems)||Principal habitat||Harmful (pest or invasive)|
|Managed grasslands (grazing systems)||Principal habitat||Natural|
|Disturbed areas||Principal habitat||Natural|
|Rail / roadsides||Principal habitat||Natural|
|Urban / peri-urban areas||Principal habitat||Natural|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details||Natural|
|Natural grasslands||Principal habitat||Harmful (pest or invasive)|
|Natural grasslands||Principal habitat||Natural|
|Wetlands||Present, no further details|
|Scrub / shrublands||Present, no further details||Natural|
|Coastal areas||Present, no further details||Natural|
Hosts/Species AffectedTop of page
In Victoria, Australia, A. odoratum is seen as a threat to the survival of some rare and threatened native ground-cover species. For example, it invades the preferred habitat of wrinkled buttons (Leiocarpa gatesii), a small annual species restricted to a small area. Invasion by this and other weed species is seen as the most serious threat facing the Gorae leek orchid (Prasophyllum diversiflorum), an endangered species known from only six isolated populations (University of Queensland, 2013).
List of Symptoms/SignsTop of page
|Cardiovascular Signs / Tachycardia, rapid pulse, high heart rate||Sign|
|Digestive Signs / Abdominal distention||Sign|
|Digestive Signs / Anorexia, loss or decreased appetite, not nursing, off feed||Sign|
|Digestive Signs / Bloody stools, faeces, haematochezia||Sign|
|Digestive Signs / Melena or occult blood in faeces, stools||Sign|
|General Signs / Dehydration||Sign|
|General Signs / Forelimb lameness, stiffness, limping fore leg||Sign|
|General Signs / Forelimb swelling, mass in fore leg joint and / or non-joint area||Sign|
|General Signs / Generalized lameness or stiffness, limping||Sign|
|General Signs / Generalized weakness, paresis, paralysis||Sign|
|General Signs / Haemorrhage of any body part or clotting failure, bleeding||Sign|
|General Signs / Hindlimb lameness, stiffness, limping hind leg||Sign|
|General Signs / Hindlimb swelling, mass in hind leg joint and / or non-joint area||Sign|
|General Signs / Inability to stand, downer, prostration||Sign|
|General Signs / Internal abdominal mass, swellings, adhesions abdomen||Sign|
|General Signs / Pale mucous membranes or skin, anemia||Sign|
|General Signs / Petechiae or ecchymoses, bruises, ecchymosis||Sign|
|General Signs / Sudden death, found dead||Sign|
|General Signs / Swelling skin or subcutaneous, mass, lump, nodule||Sign|
|Nervous Signs / Dullness, depression, lethargy, depressed, lethargic, listless||Sign|
|Pain / Discomfort Signs / Colic, abdominal pain||Sign|
|Reproductive Signs / Bloody milk, red, pink, brown milk||Sign|
|Respiratory Signs / Dyspnea, difficult, open mouth breathing, grunt, gasping||Sign|
Biology and EcologyTop of page
2n = 20. A. odoratum is almost completely self-incompatible (Borrill, 1963) although a small amount of self-fertilization can occur (Antonovics, 1968). This, combined with prolific seed production (Lambrechtsen, 1968) and rapid turnover of populations (Lambrechtsen, 1968; Antonovics, 1972) means that adaptation of the species to different conditions is often rapid. For example, Snaydon (1970) reported the evolution of specific adaptation and possibly of increased adaptability among populations in less than 40 years and over distances of less than 30 m. Furthermore, Freeland et al. (2010) have established that nutrient additions have resulted in genome-wide divergence (not just in characteristics subject to selection) between experimental plots in the same field over fewer than 75 generations, despite the high potential for ongoing gene flow. This means that A. odoratum can change both phenologically and genetically over a remarkably short time to adapt to local conditions – a reason for its great success as a colonizer of new habitats and as an invasive species.
Lambrechtsen (1968) in his thesis on A. odoratum in New Zealand observed that its seed is light, germinates quickly in light and has no dormancy or only a short dormancy period. The seedlings establish and develop rapidly, with minimal environmental requirements, quickly forming tillers. Flowering was initiated by three months of short-day periods followed by about 10 days at about 5°C. Subsequent emergence of the panicle is influenced by both day length and temperature (Lambrechtsen, 1968). In the field, the species is often reported as flowering early in the season (Hubbard, 1984; Pitcher and Russo, 1988).
The species is protogynous, the long and feathery stigmata being exserted some time before the anthers, reducing considerably the likelihood of self-fertilisation (Lambrechtsen, 1968). Seed production is copious. Lambrechtsen (1968) recorded about 30,000 seeds per plant, but mentioned that other authors had reported smaller numbers. The same author went on to say that although seeds germinate readily in the light, if buried they can remain viable in the soil for five years or more. Milton (1936), reported in Lambrechtsen (1968), found up to 6.2 million A. odoratum seeds per hectare in fields with swards up to five years old, and up to 11.25 million seeds per hectare in fields with swards more than five years old.
Physiology and Phenology
Harris (1961) showed that A. odoratum seed sown in the field germinated both in autumn and in spring, and even in the next autumn. Most growth of A. odoratum takes place in autumn or early winter and in spring or early summer (Lambrechtsen, 1968). The roots are relatively shallow (Pitcher and Russo, 1988), so plants only absorb nutrients from the upper 10 cm of soil.
A. odoratum is well known for its sweet smell, characteristic of new-mown hay, caused by the organic compound coumarin. Although coumarins in spoilt, mouldy hay containing Melilotus spp. can cause ‘sweet clover disease’ in cattle and sheep, their concentrations in Anthoxanthum species appear to be too low to cause any problems (Davies and Ashton, 1964). These coumarins may play a part in the allelopathic activity of the species -- chemicals produced by its roots inhibit the germination of seed of other species without affecting its own (Scott, 1975). Yamamoto (1995) also considered the allelopathic activity of A. odoratum invading Zoysia grassland in Japan.
Plants can live for 3 to 5 years (Lambrechtsen, 1968); Antonovics (1972) suggested that in practice the half-life of a population is about 2 years. However, seeds buried in the soil can last for 5 years or more and large populations can accumulate in seed banks in the soil (Milton, 1936).
Population Size and Structure
In a study of populations of A. odoratum in North Carolina, Grant and Antonovics (1978) found that populations varied from 28 to 99 plants m-2 in a ‘moderate to high population density’ successional old field over a two-year period, with lower densities in a nearby young pine (Pinus taeda) woodland and in the ecotone between them. In the open field, plants were much larger, with more tillers than in the other two habitats. Furthermore the population in the field was made up of older individuals than in the other locations.
A. odoratum seems to be able to grow at low levels of soil nutrients, although the level of nutrition plants require depends on where they were originally grown (Lambrechtsen, 1968). Thus plants from a montane locality took up decisively different amounts of P and S when compared to plants from four lowland localities.
In the famous Park Grass Experiment at Rothamsted, UK, the long-term fertilizer and liming treatments have caused large differences in soil chemical composition between plots but A. odoratum occurs on almost every plot of the experiment, and therefore grows on soils with widely different contents of N, P, K, Mg and Na, and with soil pH values ranging from 3 7 to 7.5 (Davies and Snaydon, 1973).
Given the wide variety of habitats in which A. odoratum occurs, it associates with very many other species. It is perhaps most commonly found in pastures or grassland, where it associates with other common grassland species like Lolium perenne, Dactylis glomerata, and Holcus lanatus.
A. odoratum is a species of temperate climates that can tolerate a wide variety of habitats, rainfall amounts, soil types and soil nutrient levels.
ClimateTop of page
|C - Temperate/Mesothermal climate||Preferred||Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C|
Soil TolerancesTop of page
- very acid
Special soil tolerances
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
Notes on Natural EnemiesTop of page
A. odoratum is presumably susceptible to many of the insects, fungi, nematodes and viruses that attack a wide range of grasses in every country. For example, in New Zealand Lambrechtsen (1968) recorded a few natural enemies of the species, including the fungi Aspergillus sp., Claviceps purpurea, Helminthosporium dematioideum [Drechslera dematioidea], Pithomyces chartarum, Puccinia graminis, Puccinia poae-nemoralis [P. brachypodii], Tilletia anthoxanthi and Epichloe typhina, the viruses cereal yellow dwarf virus and a mosaic virus, and some insects: the leaf-mining flies Cerodontha denticornis and Hydrellia tritici, the thrips Chirothrips manicatus, Chirothrips (?) pallidicornis and Aptinothrips rufus, and the larvae of the beetle Costelytra zealandica.
Means of Movement and DispersalTop of page
Natural Dispersal (Non-Biotic)
The seeds are light and may be carried a short distance in air currents.
Vector Transmission (Biotic)
Lambrechtsen (1968) said that the long barbed awn and hairy spikelet easily hook onto animals and probably even birds so that animals may contribute markedly to the distribution of A. odoratum seed.
Accidental introduction of the species, probably in hay and straw, must have occurred in the past, but accidental introduction to new countries would probably now be restricted by modern phytosanitary requirements.
In the past this species has been seen as a useful pasture component and although it is not highly regarded at the present time, it might still be deliberately introduced as a possible pasture species.
Pathway CausesTop of page
Impact SummaryTop of page
|Economic/livelihood||Positive and negative|
Economic ImpactTop of page
Although A. odoratum has been considered to be a useful pasture plant, Lambrechtsen (1968) reviewed production figures for different species and found that although there was variation in earlier workers’ results, in most cases A. odoratum produced less forage than other pasture plants like Lolium perenne. In pastures and grassland it may replace more valuable plants.
Although A. odoratum contains coumarins, the compounds which in spoilt, mouldy hay containing Melilotus spp. can cause ‘sweet clover disease’ in cattle and sheep, their concentrations in Anthoxanthum species appear to be too low to cause any problems (Davies and Ashton, 1964). On the other hand A. odoratum is mentioned by White (2014) as a cause of such poisoning.
Environmental ImpactTop of page
Impact on Habitats
The environmental impact of this species is probably similar to that of any other ‘weedy’ perennial grass. According to Pitcher and Russo (1988) it is not at present seen as a significant threat to Californian Nature Conservancy preserves, but at least in some of those reserves, elimination is the ultimate goal. According to sources cited in Cal-IPC (2013), it invades disturbed areas and prevents re-establishment of native species, but is not observed to completely displace either native or non-native plants, even as a dominant species in heavily invaded areas. In southern British Columbia, it is reported that it is rapidly invading the moss-covered bedrock coastal bluffs and will soon exclude many native species (Allred and Barkworth 2006). In Australia it is often a weed of remnant native grassy vegetation, where it can form dense swards that suppress and replace native groundcover species (University of Queensland, 2013).
Impact on Biodiversity
In Victoria, Australia, A. odoratum is seen as a threat to the survival of some rare and threatened native ground-cover species. For example, it invades the preferred habitat of wrinkled buttons (Leiocarpa gatesii), a small annual species restricted to a small area. Invasion by A. odoratum and other weed species is seen as the most serious threat facing the Gorae leek orchid (Prasophyllum diversiflorum), an endangered species known from only six isolated populations (University of Queensland, 2013). In New South Wales and the Australian Capital Territory, A. odoratum is abundant at two of the three known sites where the Tarengo leek orchid (Prasophyllum petilum) still exists, and considered to be the most serious threat to its survival at one of them.
Threatened SpeciesTop of page
|Threatened Species||Conservation Status||Where Threatened||Mechanism||References||Notes|
|Leiocarpa gatesii||National list(s)||Victoria||Competition - monopolizing resources||University of Queensland, 2013|
|Prasophyllum diversiflorum||National list(s)||Victoria||Competition - monopolizing resources||University of Queensland, 2013|
|Prasophyllum petilum||National list(s)||New South Wales||Competition - monopolizing resources||University of Queensland, 2013|
|Phyllostegia racemosa (kiponapona)||NatureServe; USA ESA listing as endangered species||Hawaii||Competition - monopolizing resources||US Fish and Wildlife Service, 2001|
|Speyeria zerene hippolyta (Oregon silverspot butterfly)||USA ESA listing as threatened species||California; Oregon||Ecosystem change / habitat alteration||US Fish and Wildlife Service, 1998|
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Has a broad native range
- Is a habitat generalist
- Fast growing
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- Has high genetic variability
- Ecosystem change/ habitat alteration
- Negatively impacts animal health
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
- Competition - monopolizing resources
UsesTop of page
A. odoratum has in the past been regarded as a useful pasture plant, but ceased to be so regarded because of its low productivity and palatability relative to other grasses (Lambrechtsen, 1968). Davies (1925) found that it was grazed by sheep in autumn, winter and early spring but hardly in summer. He considered it not very palatable.
Uses ListTop of page
Animal feed, fodder, forage
- Essential oils
Similarities to Other Species/ConditionsTop of page
A related annual species, A. aristatum, originally from the Mediterranean, North Africa and Western Asia, is now naturalized in the United States, Australia, and elsewhere, but is not as widespread as A. odoratum (and does not seem to pose so many problems). The University of Queensland (2013) notes that ‘Sweet vernal grass (A. odoratum) is very similar to the relatively rare introduced species A. aristatum, which is only naturalized in some parts of Victoria. However, A. aristatum is a short-lived (i.e. annual) species that does not form large tufts and has relatively loose seed-heads.’ A. aristatum also differs from A. odoratum in being a branched annual with glabrous glumes and awns 4-5 mm long, much longer than the glumes (C. Parker, consultant, UK, personal communication, 2014).
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Hand pulling or hoeing is an effective if labour intensive method of control. Mowing before seeds have matured may reduce or delay seed set but if moisture is adequate the plants will regrow and flower again.
Grasses have rarely been successfully targeted in biocontrol activities because too many useful grasses might also be affected.
Many herbicides (for example glyphosate) give excellent control of A. odoratum but will also kill other grasses or other species that they contact. Pitcher and Russo (1988) suggest that dalapon could be useful: it kills other grasses, but not broadleaf plants. Dalapon is also recommended in the Florabase database (Western Australian Herbarium, 2013). More modern herbicides like fluazifop-butyl or haloxyfop also kill most grasses without damaging broad-leafed plants. Spot treatment or broadcast spraying with herbicides is possible, but bare areas must be resown with desirable species as soon as possible afterwards.
Cattle and sheep readily graze A. odoratum in most seasons, but it may become less palatable in summer, possibly because of higher levels of coumarin (Lambrechtsen, 1968).
ReferencesTop of page
Allred KW, Barkworth ME, 2006. Anthoxanthum L. In: Flora of North America, North of Mexico, Volume 24: Magnoliophyta: Commelinidae (in part): Poaceae, part 1 [ed. by Flora of North America Editorial Committee \Barkworth, M. E. \Capels, K. M. \Long, S. \Anderton, L. K.]. USA: Oxford University Press. http://herbarium.usu.edu/webmanual/info2.asp?name=Anthoxanthum_odoratum&type=treatment
Buthod AK, Hoagland BW, 2011. New to Oklahoma: Anthoxanthum odoratum L. (Poaceae). Phytoneuron, 51:1-2.
Cal-IPC (California Invasive Plant Council), 2004. Cal-IPC Plant Assessment Form for Anthoxanthum odoratum. Berkeley, California, USA: California Invasive Plant Council. http://www.cal-ipc.org/paf/site/paf/257
Clayton WD, Vorontsova MS, Harman KT, Williamson H, 2013. GrassBase - The Online World Grass Flora. http://www.kew.org/data/grasses-db/
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Davies EG, Ashton WM, 1964. Coumarin and related compounds of Anthoxanthum puelii and Melilotus alba and dicoumarol formation in spoilt sweet vernal and sweet clover hay. Journal of the Science of Food and Agriculture, 15:733-738.
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ContributorsTop of page
09/04/13: Original text by:
Ian Popay, consultant, New Zealand, with the support of Landcare Research.
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