Cow parsnip (Heracleum sphondylium)

Present distribution

Scientific name:	Heracleum sphondylium L.
Common name(s):	Cow parsnip, hog weed

This weed is not known to be naturalised in Victoria

Habitat:

Native to Europe, temperate Asia & Morocco (GRIN 2008) subspecies montanum native to North America (PFAF 2005). In UK common in hedge rows, roadsides, wasteland, meadows & abandoned paddocks, also occurs in montane & coastal grassland, coastal cliffs, dunes, riverbanks, deciduous & some coniferous forests, wet sub-alpine meadows, edges of swamps, salt marsh (Sheppard 1991) & on stony slopes (Tutin et al 1968). In Europe, mountainous areas, open woodlands, sub-alpine tall herb grassland (Reed 1977, Sheppard 1991). In New Zealand on the coast in waste places, gardens & stream sides (Roy et al 2004). In USA, rich damp soils of prairies & mountains, especially along streams & in open woods (PFAF 2005) & mature aspen forest to 3000 m (Ralphs & Pfister 1992, Hoffman 1985). Also in perennial crops such as vineyards & orchards, occasionally in cereal or potato crops (Hanf 1983). In Europe, exists broadly within mean annual temperatures of 5-15^oC & rainfall of 700-5000 mm/year (Sheppard 1991).

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:
Forestry, horticulture perennial; pasture dryland; pasture irrigation.

Broad vegetation types
Coastal scrubs and grassland; grassland Coastal; grassy/heathy dry forest; lowland forest; foothills forest; forby forest; damp forest; riparian; wet forest; high altitude shrubland/woodland; alpine treeless; granitic hillslopes; basalt grassland; alluvial plains grassland; alluvial plains woodland; riverine woodland/forest.

Colours indicate possibility of Heracleum sphondylium 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 cow parsnip

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Can grow to height of 2 m (Sheppard 1991) and occurs along riverbanks (Hanf 1983). Potential to impede individual access to waterways.	ML	MH
2. Reduce tourism?	‘High-density stands of H. sphondylium develop most frequently in neutral grassland communities (Sheppard 1991)’, and as a large leaved plant it would be obvious to the ‘average’ visitor having a minor affect on the aesthetics of an area. There was no information to suggest it would impact on recreational uses.	ML	MH
3. Injurious to people?	If the juice and hairs of the outer skin are left on the face and mouth, they can cause blisters (PFAF 2005)’, causes significant photo-toxic reactions/ dermatitis (DermNet NZ 2007, Sheppard 199, Zobel & Brown 1990). Many members of this genus, including many of the sub-species in this species contain furanocoumarins. These have carcinogenic, mutagenic and phototoxic properties (PFAF 2005). The level of toxicity of this particular species and/or its subspecies is not clear from the available information, but there is potential for it to be extremely toxic.	H	M
4. Damage to cultural sites?	No information was found to indicate it would impact on cultural sites or infrastructure and as a herbaceous perennial (Hoffman 1985) it is likely to have little effect.	L	MH
Abiotic
5. Impact flow?	Occurs on riverbanks (Hanf 1983) but intolerant of waterlogging (Sheppard 1991) so unlikely to occur within waterways. Little or negligible affect on water flow.	L	H
6. Impact water quality?	Occurs on riverbanks (Hanf 1983) but intolerant of waterlogging (Sheppard 1991) so unlikely to occur within waterways. Little or negligible affect on water quality.	L	H
7. Increase soil erosion?	Root system begins as a taproot, and a system of outer vegetative meristems and associated secondary taproots enlarges the root crown (Sheppard 1991). Because it does not have a spreading root system and dies back each year (Sheppard 1991), there is potential for it to increase soil erosion if it displaces species with more substantial root systems, leaving bare unstable ground. Occurs in riparian areas (Hanf 1983). Moderate probability of large scale soil movement	ML	MH
8. Reduce biomass?	Can grow to a height of 2 m and ‘high-density stands’ can occur in grassland communities (Sheppard 1991)’. May increase biomass.	L	MH
9. Change fire regime?	Its capacity to alter the fire regime of habitats in which it occurs is not clear from available information.	M	L
Community Habitat
10. Impact on composition (a) high value EVC	In UK: ‘High-density stands of H. sphondylium develop most frequently in neutral grassland communities...It may also persist in (or invade) these communities as they become dominated by long lived perennials, often until a dense scrub or woodland canopy has developed… [it has] the facility to expand leaves early, before associated grasses. Often above-ground biomass is dominated by H. sphondylium early in the year (Sheppard 1991)’. Level to which it displaces other species not clear, no information outside native range.	M	L
(b) medium value EVC	In UK: ‘High-density stands of H. sphondylium develop most frequently in neutral grassland communities...It may also persist in (or invade) these communities as they become dominated by long lived perennials, often until a dense scrub or woodland canopy has developed… [it has] the facility to expand leaves early, before associated grasses. Often above-ground biomass is dominated by H. sphondylium early in the year (Sheppard 1991)’. Level to which it displaces other species not clear, no information outside native range.	M	L
(c) low value EVC	In UK: ‘High-density stands of H. sphondylium develop most frequently in neutral grassland communities...It may also persist in (or invade) these communities as they become dominated by long lived perennials, often until a dense scrub or woodland canopy has developed… [it has] the facility to expand leaves early, before associated grasses. Often above-ground biomass is dominated by H. sphondylium early in the year (Sheppard 1991)’. Level to which it displaces other species not clear, no information outside native range.	M	L
11. Impact on structure?	‘High-density stands of H. sphondylium develop most frequently in neutral grassland communities… [it has] the facility to expand leaves early, before associated grasses. Often above-ground biomass is dominated by H. sphondylium early in the year (Sheppard 1991)’. Level of impact on structure not clear, no information outside native range.	M	L
12. Effect on threatened flora?	No information to suggest an additional impact on threatened flora.	MH	L
Fauna
13. Effect on threatened fauna?	No information to suggest an additional impact on threatened fauna.	MH	L
14. Effect on non-threatened fauna?	Little information documented on species outside its native range, impact on native fauna unknown.	M	L
15. Benefits fauna?	‘…80% of nests [of passerine, Millaria calandra] were under Hogweed Heracleum sphondylium, possibly because this provided cover against predation and the weather (Hartley et al 1995)’. Documented to be consumed by sheep, cattle and rabbits (Haeggstroem 1990, Sheppard 1991). Though benefit to native fauna unknown, it may provide some assistance in food or shelter to desirable species.	MH	MH
16. Injurious to fauna?	Documented to be consumed by sheep, cattle and rabbits (Haeggstroem 1990, Sheppard 1991), however also documented to possess toxic properties affecting humans (PFAF 2005, Zobel & Brown 1990, Sheppard 1991). It is unknown if its toxicity would affect native fauna.	M	L
Pest Animal
17. Food source to pests?	Foliage consumed by rabbits (Sheppard 1991).	MH	H
18. Provides harbour?	Hartley et al (1995) found that 80% of nests of passerine, Millaria calandra, were under Hogweed Heracleum sphondylium, ‘possibly because this provided cover against predation and the weather (Hartley et al 1995)’. Can grow to a height of 2 m and ‘high-density stands’ can occur in grassland communities (Sheppard 1991)’. Has potential to provide short term harbour to rabbits.	MH	MH
Agriculture
19. Impact yield?	‘H. sphondylium is rarely a weed of arable crops, partly because it cannot survive regular ploughing…although is possibly becoming a more serious problem under minimum tillage (Sheppard 1991)’, and does occur in perennial crops such as vineyards & orchards (Hanf 1983). It is stated to be resistant to most herbicides (Sheppard 1991), and although not documented, there is potential for to have a minor impact on yield in perennial crops or lower soil disturbance agricultural situations.	ML	M
20. Impact quality?	No information was found to suggest it would to impact on agricultural quality.	L	M
21. Affect land value?	No information was found to suggest it would affect land value.	L	M
22. Change land use?	No information was found to suggest it would cause a change in land use.	L	M
23. Increase harvest costs?	Documented as resistant to most herbicides (Sheppard 1991) so control may involve a larger outlay of time and costs leading to minor increase in overall production costs.	M	M
24. Disease host/vector?	Known to be a host of several viruses that infect cultivated Umbelliferous species, e.g. parsnips, carrots. Also a host for aphids (Bem & Murant 1979).	M	H

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	‘There was virtually no emergence during the Autumn of sowing, the main emergence was in late winter early spring (Roberts 1979)’. Hoffman (1985) found it to germinate only after 120 days stratification. Requires natural seasonal disturbances for germination. ‘The Mediterranean region represents a southern limit to the distribution of this species, probably because minimum winter temperatures are too high for the after-ripening requirements of seeds and the extended drought periods affect seedling survival (Sheppard 1991)’. These factors may also restrict its distribution in certain areas of Victoria.	MH	H
2. Establishment requirements?	‘Light requirements are also low. Hercaleum sphondylium is a common species of deciduous woodland down to light levels of c. 5% daylight on the forest floor, but it does not persist beyond the shade tolerance of most under storey herbs (e.g. under dense coniferous canopies) (Sheppard 1991)’. Can establish under moderate canopy.	MH	H
3. How much disturbance is required?	‘Typical habitats include hedge rows, road verges, wasteland, meadows and abandoned paddocks’ but also occurs in woodlands, forests, tall herb montane grassland, coastal grassland on ‘old fixed grey-dunes’ and on riverbanks (Sheppard 1991). ‘Abundance of H. sphondylium is not limited by the successional stage of the community (Sheppard 1991)’. Appears able to establish in minor disturbed natural ecosystems, e.g. riparian, grassland, woodland.	MH	H
Growth/Competitive
4. Life form?	Herbacious perennial (Hoffman 1985). Lifeform: other	L	H
5. Allelopathic properties?	‘Allelopthy is suggested to account for a minor part of the suppressed plant production under a H. laciniatum [synonym] canopy (Myras & Olavi 1981)’. Minor properties.	ML	H
6. Tolerates herb pressure?	‘Cattle and sheep regularly remove all above-ground foliage…If less than half of the foliage is removed there is little effect on seed production. However greater defoliation by selective grazing will result in a reduction in seed number (Sheppard 1991)’. Potential for seed production to be strongly inhibited by herbivory due to preference of herbs by stock.	ML	H
7. Normal growth rate?	Some strength as a competitor may come from the extensive carbohydrate store in its perennial tap root and the facility to expand leaves early. Often above-ground biomass is dominated by H. sphondylium early in the year (Sheppard 1991)’. Potential for growth rate to exceed most other species of the same life form.	H	MH
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Occurs at 3000 m in Central Utah USA (Ralphs & Pfister 1992). ‘…requires non-waterlogged soil…grows in soil where moderate salinity arises from sea spray and not inundation by salt-water (Sheppard 1991)’. Documented in salt marsh communities (Sheppard 1991). The large taproots provide protection against drought for mature plants (Sheppard 1991)’. Highly tolerant of frost, moderately drought and salt tolerant, susceptible to waterlogging. Large taproot likely to provide some fire tolerance.	MH	H
Reproduction
9. Reproductive system	‘Reproduction is almost entirely from seed [both cross and self-pollination occur] (Sheppard 1991)’. ‘Vegetative reproduction is not important (Sheppard 1991)’. Sexual reproduction (self and cross pollination).	ML	H
10. Number of propagules produced?	‘Typical annual seed number produced per flowering plant is highly variable, ranging from 0 to 5000 (Sheppard 1991)’. Large, old individuals in good growing conditions can produce up to 20,000 seeds per season. Individuals on dry relatively nutrient-poor sites (e.g. sand dunes) can produce little or no seed, and shaded plants have low seed production (Sheppard 1991)’. Potential to produce above 2000 seeds per flowering event.	H	H
11. Propagule longevity?	‘Few viable seeds remained after a year…and practically no seeds survived beyond the second year (Roberts 1979)’. After 2 years <1% of seeds surviving in soil (Silvertown & Tremlett 1989)’.	L	H
12. Reproductive period?	‘…perennial and not a biennial as often stated…Flowering does not normally occur until at least the third Summer…The plant is known to have the capacity to flower in at least 8 further seasons, although 2 or 3 is the norm (Sheppard 1991)’. Mature plant produces viable propagules for 3-10 years.	MH	H
13. Time to reproductive maturity?	‘…perennial and not a biennial as often stated…Flowering does not normally occur until at least the third Summer (Sheppard 1991). 2-5 years to reach reproductive maturity.	ML	H
Dispersal
14. Number of mechanisms?	‘Seed dispersal is passive and normally by wind alone (Sheppard 1991)’. Seeds large (Thompson & Baster 1992).	MH	H
15. How far do they disperse?	‘[Seeds] are blown from the umbels in dry winds and settle close to the parent plant in the same habitat. Casual observation suggests few mericarps travel more than 50m (Sheppard 1991)’. Very unlikely to disperse greater than 200m, most likely to travel less than 20m.	L	H

References

Bem F. & Murant 1979, ‘Transmission and differentiation of six viruses infecting hogweed (Heracleum sphondylium) in Scotland’, Annals of Applied Biology, 92, 237-242.

DermNet New Zealand (DermNet NZ) 2007, Cow parsnip/ hogweed, New Zealand Dermatological Society Incorporated, viewed: 5/3/2008, http://dermnetnz.org/dermatitis/plants/hogweed.html

Haeggstroem, C.A. 1990, ‘The influence of sheep and cattle grazing on wooded meadows in Aaland, SW Finland’, Acta Botanica Fennica, 141, 28.

Hanf, M. 1983, The Arable Weeds of Europe: with their seedlings and seeds, BASF United Kingdom Limited For BASF Aktiengesellschaft D-6700 Ludwigshafen.

Hartley, I.R., Shepherd, M. & Thompson, D.B.A. 1995, ‘Habitat selection and polygyny in breeding corn buntings Milliaria calandra’, Ibis. 137 (4). 508-514

Hoffman, G.R. 1985, ‘Germination of herbaceous plants common to aspen forests of western Colorado’, Bulletin of the Torrey Botanical Club. 112 (4), 409-413.

Myras, H. & Olavi, J 1981, ‘Interaction between Heracleum lacinatum and some other plants’, Holarctic Ecology, 4(1), 43-48.

Plants For a Future Database (PFAF) 2005, Heracleum sphondylium, viewed: 29/2/2008, http://www.pfaf.org/database/plants.php?Heracleum+sphondylium

Ralphs, M. H. & Pfister, J.A. 1992, ‘Cattle diets in tall forb communities on mountain rangelands’, Journal of Range Management, 45, 534-537.

Reed, C.F. 1977, Economically important foreign weeds: Potential problems in the United States, Agriculture handbook No. 498, United States Department of Agriculture.

Roberts, H.A. 1979, ‘Periodicity of Seedling Emergence and Seed Survival in some Umbelliferae’, Journal of Applied Ecology. 16 (1), 195-201

Roy, B., Popay, I., Champion, P., James, T. and Rahman, A. 2004, An illustrated guide to the common weeds of New Zealand, 2nd ed., New Zealand
Plant Protection Society, Hastings.

Sheppard, A.W. 1991, ‘Biological Flora of the British Isles: No. 171- Heraclem sphondylium L.’, Journal of Ecology, 79, 235-258.

Silvertown, J. & Tremlett, M. 1989, ‘Interactive effects of disturbance and shade upon colonization of grassland: and experiment with Anthriscus sylvestris (L.) Hoffm., Conium maculatum L., Daucus carota L. and Heracleum sphondylium L’, Functional Ecology. 3 (2). 229-235.

Thompson, K. & Baster, K. 1992, ‘Establishment from seed of selected Umbelliferae in unmanaged grassland’. Functional Ecology. 6 (3), 346-352

Tutin, T.G., Heywood, V.H., Burges, N.A., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb D.A (1968), Flora Europaea: Volume 2- Rosaceae To
Umbelliferae, Cambridge at the University Press.

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network – (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville Maryland, viewed: 5/1/2008, www.ars-grin.gov/cgi-bin/npgs/html/genform.pl

Zobel, A.M. & Brown, S.A. 1990, ‘Seasonal changes of furanocoumarin concentrations in leaves of Heracleum lanatum’, Journal of Chemical Ecology. 16 (5), 1623-1634.

Global present distribution data references

Global Biodiversity Information Facility (GBIF) 2007, Global biodiversity information facility, viewed: 29 FEB 2008, http://www.gbif.org/

Missouri Botanical Gardens (MBG) 2007, w³TROPICOS, Missouri Botanical Gardens Database, viewed 29 FEB 2008, http://mobot.mobot.org/W3T/Search/vast.html

Roy, B., Popay, I., Champion, P., James, T. and Rahman, A. 2004, An illustrated guide to the common weeds of New Zealand, 2nd ed., New Zealand Plant Protection Society, Hastings.

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