Creeping fog grass (Holcus mollis)

Present distribution

Scientific name:	Holcus mollis L.
Common name(s):	Creeping fog grass

Map showing the present distribution of this weed.

Habitat:

Native to Europe, excluding some northern and SE regions (Walter 1973). A weed in many countries including Argentina, North America, Australia, New Zealand, South Africa & the UK (Walsh & Entwisle 1994, Parodi 1937, Wells 1986, Walter 1973). Occurs in ‘broom scrub’, woodland (Cornide et al 2005, Sevillano & Vazquez 1999), forests (Taborsky et al 2002, Lawesson & Wind 2002), prairie remnants, oak savannahs (USU 2002), drier valley flats, grassland, grassy & shrubby heaths often associated with bracken, on moist, free draining & often acid soils but tolerant of a range of soils including very dry poor sandy soils (Bond et al 2006, Walter 1973, Ovington 1953). Occurs in montane (Dvorak 1973) & alpine regions (FAO 2004). A weed of horticultural crops such as potatoes (Dvorak 1973), raspberries & boysenberries (Renfrow 1961), plantations (Van Goor & Jager 1962), pasture (USU 2002), cultivated fields, barley & oat crops (Walter, 1973 Mann & Barnes 1947). In Australia occurs in NSW, Victoria & Tasmania with potential to become a serious weed of damp & sandy areas (Richardson 2006).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Broadacre cropping; forest private plantation; forest public plantation; horticulture; pasture dryland; pasture irrigation

Broad vegetation types
Coastal scrubs and grassland; coastal grassy woodland; heathy woodland; lowland forest; heath; swamp scrub; box ironbark forest; inland slopes woodland; sedge rich woodland; dry foothills forest; moist foothills forest; montane dry woodland; montane moist forest; sub-alpine woodland; grassland; plains grassy woodland; valley grassy forest; herb-rich woodland; sub-alpine grassy woodland; montane grassy woodland; riverine grassy woodland; riparian forest; rainshadow woodland; mallee heath; mallee woodland; Wimmera / mallee woodland.

Colours indicate possibility of Holcus mollis infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

map showing the potential distribution of creeping fog grass

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Its habit as a grass, around 45 cm in height with ‘flimsy’ stems (Darke & Griffiths 1994), makes it unlikely to restrict human access.	L	M
2. Reduce tourism?	Its habit as a grass, around 45 cm in height with ‘flimsy’ stems (Darke & Griffiths 1994) makes it unlikely to impact on recreational uses. It may however have a minor negative affect on the aesthetics of an area due to its capacity to form large clonal patches reaching 100 m across (Bond et al 2006).	ML	M
3. Injurious to people?	There is no information found to suggest it is injurious to people.	L	ML
4. Damage to cultural sites?	Due to its low growing habit (Darke & Griffiths 1994), it is likely to have little negative affect on infrastructure or cultural sites.	L	M
Abiotic
5. Impact flow?	A terrestrial species, not likely to impact on water flow.	L	M
6. Impact water quality?	A terrestrial species, not likely to impact on water quality.	L	M
7. Increase soil erosion?	Holcus mollis possesses a system of densely matted rhizomes (Whitson et al 1992) with the horizontal length of rhizomes reaching about 5 m (Bond et al 2006). It is therefore unlikely that the presence of Holcus mollis would lead to an increase in soil movement, and in some circumstances it may decrease the probability of soil erosion.	L	M
8. Reduce biomass?	H. mollis has an extensive rhizome system, and in one study, 7 ½ tones of rhizome growth was produced in just 10 months (Mann & Barnes 1947). There is potential for the biomass of a community to be increased by the presence of H. mollis due its large underground rhizome system.	L	M
9. Change fire regime?	While no information specific to H. mollis was found documented, being a grass with the capacity to grow in large swards and under shaded canopies (Bond et al 2006), it has the potential to increase fire frequency while reducing fire intensity, and also reducing vertical continuity of fuels (Brooks et al 2004). This could impact on communities that need less frequent but more intense crown fires, e.g., forest communities. However, similar species H. lanatus was found to be absent from frequently burnt areas in a Victorian grassland while being common in unburnt areas, suggesting fire may not promote invasion of Holcus species. Not enough information is available to propose the impact H. mollis would have on fire regimes.	M	L
Community Habitat
10. Impact on composition (a) high value EVC	EVC= Creekline grassy woodland (BCS= E); CMA= Wimmera; Bioreg= Greater Grampians; CLIMATE potential=VH. Holcus mollis excludes other vegetation due to its densely matted rhizomes (Whitson et al 1992) and forms large clonal patches reaching 100 m across (Bond et al 2006). It can spread very rapidly and suppress or eliminate most other vegetation (Lee 1969). Potential to cause major displacement of some dominant species, within the lower strata.	MH	MH
(b) medium value EVC	EVC= Damp heathland (BCS= R); CMA= Port Phillip; Bioreg= Gippsland Plain; CLIMATE potential=VH. H. mollis excludes other vegetation due to its densely matted rhizomes (Whitson et al 1992) and forms large clonal patches reaching 100 m across (Bond et al 2006). It can spread very rapidly and suppress or eliminate most other vegetation (Lee 1969). Potential to cause major displacement of some dominant species, within the lower strata.	MH	MH
(c) low value EVC	EVC= Heathy woodland (BCS= LC); CMA= Port Phillip; Bioreg= Gippsland Plain; CLIMATE potential=VH. H. mollis excludes other vegetation due to its densely matted rhizomes (Whitson et al 1992) and forms large clonal patches reaching 100 m across (Bond et al 2006). It can spread very rapidly and suppress or eliminate most other vegetation (Lee 1969). Potential to cause major displacement of some dominant species, within the lower strata.	MH	MH
11. Impact on structure?	H. mollis excludes other vegetation due to its densely matted rhizomes (Whitson et al 1992) and forms large clonal patches reaching 100 m across (Bond et al 2006). It can spread very rapidly and suppress or eliminate most other vegetation (Lee 1969). This species would largely impact on the lower floral strata. Potential to have a major effect on <60% of the floral strata.	MH	MH
12. Effect on threatened flora?	H. mollis excludes other vegetation due to its densely matted rhizomes (Whitson et al 1992) and forms large clonal patches reaching 100 m across (Bond et al 2006). It can spread very rapidly and suppress or eliminate most other vegetation (Lee 1969). Information specifically on threatened flora species was not found documented.	MH	L
Fauna
13. Effect on threatened fauna?	The ability of H. mollis to form large colonies (Bond et al 2006), spread rapidly, and suppress or eliminate vegetation (Lee 1969) may reduce habitat & food availability for fauna species. However, no information was found documented of the affect H. mollis has on fauna, or specifically threatened fauna.	MH	L
14. Effect on non-threatened fauna?	The ability of H. mollis to form large colonies (Bond et al 2006), spread rapidly, and suppress or eliminate vegetation (Lee 1969) may reduce habitat & food availability for fauna species. However, no information was found documented of the affect H. mollis has on fauna.	M	L
15. Benefits fauna?	It is documented as being consumed by several grazing species (Williams 1976, Pavlu et al 2003, Crawley 1990) and may provide some assistance as a food source or habitat to desirable native fauna.	MH	ML
16. Injurious to fauna?	No information was found to suggest that H. mollis has any properties injurious to fauna.	L	L
Pest Animal
17. Food source to pests?	Documented as being consumed by rabbits (Crawley 1990). Provides food to a serious pest but at low levels.	MH	M
18. Provides harbour?	No information was found to suggest that H. mollis provides harbour for pest species.	L	L
Agriculture
19. Impact yield?	‘…it fills the upper layer of the soil with an almost solid mat of rhizomes. When these fields are returned to the production of cultivated crops, regrowth from the rhizome mass severely hinders or prevents crop production (Lee 1969)’. Holcus mollis can reduce barley yield by one-third or more, and is documented as having the capacity to totally eliminate barley in some circumstances (Mann & Barnes 1947). Has serious impacts on quantity >20% reduction in yield.	H	MH
20. Impact quality?	Its competitive ability, and the difficulty in removing its seed, from the seed of bentgrass, Kentucky bluegrass, and chewings fescue, results in substantial financial losses within a three-county area of Oregon (Lee 1969). Its ability to cause such financial loss is an indication that seed contamination by H. mollis has a major impact on agricultural quality.	MH	M
21. Affect land value?	Its potential serious impacts on agricultural yield, quality & land use (refer to criteria 19, 20 & 22) could result in a decrease in agricultural land value, however, no specific reference to its impact on land value was found.	M	L
22. Change land use?	‘When theses fields are returned to the production of cultivated crops, regrowth from the rhizome mass severely hinders or prevents crop production (Lee 1969)’. It is also documented as seriously reducing production of an oat crop which resulted in half of a field being left abandoned covered in a dense infestation of H. mollis (Fenton 1948). Potential to cause a down grading in the priority of land use to one with less agricultural return.	MH	MH
23. Increase harvest costs?	Two to four years of intensive cultivation are required to reduce H. mollis sufficiently to permit a return to crop production. In addition to the loss of production, this can cause a significant cost in labour, fuel and machinery (Lee 1969). The difficulty in removing H. mollis seed from the seed of several grass crop species is also documented as causing substantial financial loss (Lee 1969). Potential to cause a major increase in harvest time, labour or machinery.	H	M
24. Disease host/vector?	No information was found documented to suggest that H. mollis acts as a host or vector for diseases of agriculture.	L	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Trapaidze & Gogiya (1981) found that seeds began germinating at 7-8 ^o C but the optimum temperature was 10-15 ^o C. This is an indication that natural seasonal disturbances, such as warmer spring temperatures, may be required for germination.	MH	M
2. Establishment requirements?	Holcus mollis is a shade loving grass common in oak woods (Fenton 1948). It grows well in shaded habitats as well as open areas (Walter 1973). It is also able to grow under a large amount of bracken refuse (Ovington 1953). Can establish under a moderate canopy and litter cover.	MH	MH
3. How much disturbance is required?	In USA, H. mollis has become a problematic weed invading several communities including grasslands (prairies) & oak savannahs, and in the UK it occurs in woodland vegetation and grassy heaths (USU 2002, Bond et al 2006, Fenton 1948). Can establish in minor disturbed ecosystems, e.g. grassland, woodland, heath.	MH	M
Growth/Competitive
4. Life form?	Rhizomatous perennial grass (Walsh & Entwisle 1994). Lifeform: Grass	MH	MH
5. Allelopathic properties?	‘There have been suggestions that creeping soft-grass [Holcus mollis], reduces barley growth allelopathically (Horne 1953 in Bond et al 2006)’. From the information available it is difficult to conclude whether allelopathic properties are present in Holcus mollis.	M	L
6. Tolerates herb pressure?	There is information documented that H. mollis is consumed and decreased by grazing, does not persist under heavy grazing, and that it regenerates vegetatively, but recovers more slowly than other grasses (Bond et al 2006, Pavlu et al 2006, Crawley 1990). However, there is conflicting information documented suggesting it is consumed but not preferred by grazers (Lee 1969) and that it increases with grazing due to its ability to spread by stolons (Hill 1983, Mountford et al 2000). A medium rating has been allocated.	M	M
7. Normal growth rate?	As a ‘consequence of its rapid growth and unduly creeping habit’, Sowerby & Johnson (1861) considered it one of the most troublesome weeds and very difficult to eradicate. ‘The rapidity of the growth of the underground portion of H. mollis is very remarkable’ (Mann & Barnes 1947). An extremely vigorous and competitive grass (Lee 1969). A specimen transplanted into improved soil, increased its fresh weight by 240 times in just over a year (Ovington 1953. Rapid growth rate.	H	MH
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Its inability to tolerate prolonged, hard frosts is documented (Bond et al 2006). It is an indicator of moist conditions and a weed of damp areas (PlantNET 2007, Andries 1958) but can also tolerate very dry poor sandy soil (Walter 1973). It appears to display some tolerance to water logging, light frosts, and moderate drought conditions, but available information is limited and sometimes conflicting, and reference to other stresses was not found. Variation in stress tolerance between different populations is also documented (Walter 1973).	M	L
Reproduction
9. Reproductive system	Reproduction is via seeds & sprouting rhizomes (Wells et al 1986, Trapaidze & Gogiya 1981). In woodland, vegetative reproduction predominates (Bond et al 2006). Seed & vegetative reproduction.	H	MH
10. Number of propagules produced?	It is documented as producing large quantities of viable seed, between 174 and 820 million seeds per acre (Lee 1969). The number of propagules produced by plants is potentially high, however, no information on the production of individual plants was found documented.	M	L
11. Propagule longevity?	Lee (1969) demonstrated that after 5 years, maximum viability of seeds buried at different depths was less than 20%. In addition, less than 1% of seeds buried at a depth of 1 inch were viable after only 2. 5 years. Less than 25% of seeds survive 5 years.	L	MH
12. Reproductive period?	Forms large clonal patches reaching 100 m across (Bond et al 2006). An indication that Holcus mollis forms self sustaining monocultures.	H	MH
13. Time to reproductive maturity?	‘A plant may flower in its first year from seed (Bond et al 2006)’. Reaches maturity & produces viable propagules in less than a year.	H	MH
Dispersal
14. Number of mechanisms?	Trapaidze & Gogiya (1981) found that seeds were readily dispersed by wind.	H	MH
15. How far do they disperse?	Seeds that are readily wind dispersed have potential to travel considerable distance, so it is likely that at least one seed will disperse greater than I km.	H	M

References

Andries A 1958, ‘Grassland surveying in Belgium’, Het Wetenschappelijk Onderzoek in de Landbouw, vol. 1, pp 51-58.

Bond W, Davies G & Turner R 2006, The biology and non-chemical control of Creeping Soft-grass (pdf), HDRA Weed Management, Coventry, UK, http://www.gardenorganic.org.uk/organicweeds/downloads/holcus%20mollis.pdf

Brooks ML, D’Antonio CM, Richardson DM, Grace JB, Keeley JE, Di Tomaso JM, Hobbs, RJ, Pellant M & Pyke D 2004, ‘Effects of Invasive alien plants on fire regimes’, BioScience, vol. 54, no. 7, pp. 677-688.

Crawley MJ 1990, ‘Rabbit grazing, plant competition and seedling recruitment in acid grassland’, Journal of Applied Ecology, vol. 27, pp. 803-820.

Cornide T, Diaz-Vizcaino E & Casal M 2005, Biodiversity and dynamics of traditional silvopastoral systems in Galicia (north-west Spain): Cystisus scrubs, Silvopastoralism & sustainable land management. Proceedings of an international congress on silvopastoralism and sustainable management held in Lugo, Spain, April 2004, pp 248-250.

Darke R & Griffiths M (eds.) 1994, The New Royal Horticultural Society Dictionary- Manual of Grasses, Timber Press, Portland, Oregon.

Dvorak J 1973, Biology of Holcus mollis L., a field weed infesting mountain regions of Czechoslovakia, Jugoslovenski simpozijum o bordi protiv korava u brdsko-planinskim podrucjima, Sarajevo 1973, pp. 43-46.

Fenton EW 1948, ‘Some notes on Holcus mollis L.’, Annals of Applied Biology, vol. 35, pp. 290-292.

Food & Agriculture Organisation (FAO) 2004, Grassland Species Database, FAO crop & grassland service (AGPC), Agriculture Department, FAO, viewed: 2nd April 2007, http://www.fao.org/ag/agp/agpc/doc/Gbase/Default.htm

Hill MO 1983, ‘Effects of grazing in Snowdonia’, Annual Report 1982, Natural Environment Research Council, Institute of Terrestrial Ecology, Cambridge, UK, pp. 31-32.

Horne FR (in Bond et al 2006) 1953, The significance of weed seeds in relation to crop production, Proceedings of the 1st British Weed Control Conference, Margate, UK, 372-398.

Lawesson J E & Wind P 2002, ‘Oak dune forests in Denmark and their ecology’, Forest Ecology and Management, vol. 164, no. 1/3, pp.1-14.

Lee WO 1969, ‘Distribution, growth habits, and control of German velvetgrass in western Oregon’, Technical Bulletin of Oregon State University Agricultural Experimental Station, vol. 107? Pp. 30?

Mann H H & Barnes TW 1947, ‘The competition between barley and certain weeds under controlled conditions’, Annals of Applied Biology, vol. 34, pp. 252-266.

Mountford EP, Page PA & Peterken GF 2000, ‘Twenty-five years of change in a population of oak saplings in Wistman’s Wood, Devon’, English Nature Research Reports, vol. 348, pp. 29.

Ovington JD 1953, ‘A study of invasion by Holcus mollis L.’, Journal of Ecology, vol. 41, no. 1, pp. 35-52.

Parodi LR 1937, ‘Some exotic grasses naturalised in the Argentine Republic’, Rev. argent. Agron., vol. 4, pp. 43-50.

Pavlu V, Gaisler J, Hejcman M & Pavlu L 2006, ‘Effect of different grazing systems on dynamics of grassland weedy species’, Journal of Plant Diseases & Protection, ‘Special issue 20’, pp. 377-383.

Plantnet 2007, New South Wales Flora Online: Holcus mollis, Botanic Gardens Trust, Sydney, viewed: 16th February 2007, http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Holcus~mollis

Renfrow JF 1961, ‘Weeds in horticultural crops’, Res. Prog. Rep. Western Weed Control Conference, pp. 50-63.

Richardson FJ & RG & Shepherd RCH 2006, Weeds of the South-East: An identification guide for Australia, RG & FJ Richardson, Meredith, Victoria.

Sevillano IJ & Vazquez JA 1999, ‘The vegetation of stretch Villafranca del Bierzo-Pedrafita do Cebreiro-Linares’, Itinera Geobotanica, vol. 13, pp. 218-230.

Soweby J & Johnson H 1861 (in Mann & Barnes 1947), Grasses of Great Britain, London.

Taborsky V, Polak J, Lebeda A & Kudela V 2002, ‘Evaluation of fusariosis in selected grass species’, Plant Protection Science (Czech Republic), vol. 38, Special 2, pp. 402-405.

Trapaidze AS & Gogiya 1981, ‘Investigating the biological characteristics of Holcus and methods for its control’, Subtropicheskie, vol. 4, pp. 72-74.

Utah State University (USU) 2002, ‘Grass manual on the web’- Manual of grasses for North America Project, Intermountain Herbarium, USU, Utah, viewed 16th February 2007, http://herbarium.usu.edu/webmanual/

Van Goor CP & Jager K 1962, ‘Control of grasses in forest plantation with simazine and atrazine’, Ned.Bosb. Tijdschr., vol. 34, no. 1, pp. 34-40.

Walsh NG & Entwisle TJ (eds.) 1994, Flora of Victoria-Volume 2: Ferns & Allied Plants, Conifers and Monocotyledons, Inkata Press, Melbourne-Sydney.

Walter R 1973, ‘Holcus mollis L. in Poland. I. Karyological investigations’, Acta Biologica Cracoviensia (Series: Botanica), vol. 16, pp. 227-233.

Wells MJ, Balsinhas AA, Joffe H, Engelbrecht VM, Harding G & Stirton CH 1986, ‘A catalogue of problem plants in southern Africa incorporating the National Weeds list of southern Africa,’ Memoirs of the Botanical Survey of South Africa, vol. 53.

Whitson TD, Burrill LC, Dewey SA, Cudney DW, Nelson BE, Richard DL & Parker R 1992, Weeds of the West, Western Society of Weed Science, CA, USA.

Williams GH 1976, ‘The biology of weeds in hill pasture’, Annals of Applied Biology, vol. 83, no. 2, pp. 345-347.

Global present distribution data references

Australian National Herbarium (ANH) 2007, Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, viewed: 26th March 2007, http://www.anbg.gov.au/avh/

Department of Sustainability and Environment (DSE) 2006, Flora information system [CD-ROM], Biodiversity and Natural Resources Section, Viridans Pty Ltd, Bentleigh.

EIS: Environmental Information System 2006. Parks Victoria.

Global Biodiversity Information Facility (GBIF) 2007, Global biodiversity information facility: Prototype data portal, viewed: 26th March 2007, http://www.gbif.org/

IPMS: Integrated Pest Management System 2006. Department of Primary Industries.

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