Crofton weed (Ageratina adenophora)

Present distribution

Scientific name:	Ageratina adenophora (Spreng.) R.M. King & H.Rob.
Common name(s):	Crofton weed

Map showing the present distribution of this weed.

Habitat:

‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ ‘Most of the A. adenophora in South Africa occurs in moist habitats’ (Kluge 1991). It is frequently associated with shaded, wet areas fringing forests (including rainforest) (Land Protection QLD 2006). Persistent weed of high rainfall areas. Tolerant of wet soils and will extend to wetlands (Parsons and Cuthbertson 2001). Frost resistant but drought tender (Bodkin 1986). Occurs along creek beds, forest clearings and in areas with steep frost-free slopes where rainfall exceeds 1500 mm annually (Slotwinski 2002).

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; horticulture seasonal; pasture dryland; pasture irrigation

Ecological Vegetation Divisions
Swampy scrub; freshwater wetland (permanent); treed swampy wetland; lowland forest; forby forest; damp forest; riparian; wet forest; rainforest; alluvial plains woodland; ironbark/box; riverine woodland/forest; freshwater wetland (ephemeral)

Colours indicate possibility of Ageratina adenophora 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 of the potential distribution of agertina adenophora

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Low nuisance value. Impedes individual access; unable to walk to waterways.	ML	M
2. Reduce tourism?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Malodorous (Motooka et al. 2003). Minor effects to aesthetics.	ML	M
3. Injurious to people?	‘All parts of the plant have a strong aromatic smell when bruised, may cause allergic reactions (WBM undated). No effect, no prickles, no injuries.	L	L
4. Damage to cultural sites?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Moderate visual effect.	ML	M
Abiotic
5. Impact flow?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006).Crofton weed grows along streams. (Land Protection QLD 2006). ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ (Kluge 1991). Impacts on flow are unknown.	L	ML
6. Impact water quality?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’…Crofton weed grows along streams. (Land Protection QLD 2006). ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ (Kluge 1991). Impacts on water quality are unknown.	L	ML
7. Increase soil erosion?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Shallow but extensive fibrous root system (WBM undated) Unknown	M	L
8. Reduce biomass?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Unknown.	M	L
9. Change fire regime?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Small or negligible effect on fire risk.	L	ML
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Plains Woodland (E); CMA = North Central; Bioregion =Victorian Riverina; VH CLIMATE potential. ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ ‘Most of the A. adenophora in South Africa occurs in moist habitats’ (Kluge 1991). It is frequently associated with shaded, wet areas fringing forests (including rainforest) (Land Protection QLD 2006). Persistent weed of high rainfall areas. Tolerant of wet soils and will extend to wetlands (Parsons and Cuthbertson 2001). Frost resistant but drought tender (Bodkin 1986). Occurs along creek beds, forest clearings and in areas with steep frost-free slopes where rainfall exceeds 1500mm annually (Slotwinski 2002). Very little displacement of any indigenous species, sparse scattered infestations.	L	H
(b) medium value EVC	EVC = Heathy Herb-rich Woodland (D); CMA =Wimmera; Bioregion = Glenelg Plain; VH CLIMATE potential. ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ ‘Most of the A. adenophora in South Africa occurs in moist habitats’ (Kluge 1991). It is frequently associated with shaded, wet areas fringing forests (including rainforest) (Land Protection QLD 2006). Persistent weed of high rainfall areas. Tolerant of wet soils and will extend to wetlands (Parsons and Cuthbertson 2001). Frost resistant but drought tender (Bodkin 1986). Occurs along creek beds, forest clearings and in areas with steep frost-free slopes where rainfall exceeds 1500mm annually (Slotwinski 2002). Very little displacement of any indigenous species, sparse scattered infestations.	L	H
(c) low value EVC	EVC = Damp Forest (LC); CMA =East Gippsland; Bioregion =East Gippsland Uplands; VH CLIMATE potential. ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ ‘Most of the A. adenophora in South Africa occurs in moist habitats’ (Kluge 1991). It is frequently associated with shaded, wet areas fringing forests (including rainforest) (Land Protection QLD 2006). Persistent weed of high rainfall areas. Tolerant of wet soils and will extend to wetlands (Parsons and Cuthbertson 2001). Frost resistant but drought tender (Bodkin 1986). Occurs along creek beds, forest clearings and in areas with steep frost-free slopes where rainfall exceeds 1500 mm annually (Slotwinski 2002). Minor displacement of some dominant or indicator species within any one layer/strata (e.g. Ground cover, forbs, shrubs etc.).	ML	H
11. Impact on structure?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated). Minor effect on 20-60% of the floral strata.	ML	M
12. Effect on threatened flora?	Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated). Impacts on threatened flora are unknown.	MH	L
Fauna
13. Effect on threatened fauna?	Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated). Unpalatable to cattle and poisonous to horses (Motooka et al 2003). Impacts on threatened fauna are unknown.	MH	L
14. Effect on non-threatened fauna?	Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated).Unpalatable to cattle and poisonous to horses (Motooka et al 2003). Minor effects on fauna species, minor hazard or reduction in habitat/food/shelter.	ML	MH
15. Benefits fauna?	Unpalatable to cattle and poisonous to horses…Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated). Provides very little assistance to desirable species.	H	ML
16. Injurious to fauna?	Unpalatable to cattle and poisonous to horses (Motooka et al 2003). Toxic, and/or causes allergies.	H	MH
Pest Animal
17. Food source to pests?	Unpalatable to cattle and poisonous to horses (Motooka et al 2003), other stock eat it without ill effect (ESC NSW undated). Provides minimal food for pest species.	L	M
18. Provides harbour?	‘Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1-2 metres high’ (Land Protection QLD 2006). Doesn’t provide harbour for major pest species, may provide harbour for minor pests.	ML	M
Agriculture
19. Impact yield?	Crofton weed is an aggressive weed in pastures in the valleys and on the plateaus in south-eastern Queensland. On wet slopes it has invaded grass pasture (Land Protection 2006). If they move into run-down pasture, stock carrying-capacity can be reduced, but seedlings are not very competitive in vigorous pasture. (ESC NSW undated). Minor impact on quantity of produce (e.g. <5% reduction).	M	M
20. Impact quality?	Crofton weed is an aggressive weed in pastures in the valleys and on the plateaus in south-eastern Queensland. On wet slopes it has invaded grass pasture (Land Protection 2006). If they move into run-down pasture, stock carrying-capacity can be reduced, but seedlings are not very competitive in vigorous pasture. (ESC NSW undated). Minor impact on quality of produce (e.g. <5% reduction).	ML	M
21. Affect land value?	May be controlled by slashing, followed by ripping or ploughing, then sowing a desirable pasture species (Motooka et al. 2003). Control is best achieved by good pasture management and timely herbicide use (Land Protection QLD 2006). Displaces forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Seedlings are not very competitive in vigorous pasture. Can form dense stands on moist sites, choking out native vegetation (ESC NSW undated). Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Decreases in land value <10%	ML	MH
22. Change land use?	May be controlled by slashing, followed by ripping or ploughing, then sowing a desirable pasture species (Motooka et al. 2003). Control is best achieved by good pasture management and timely herbicide use (Land Protection QLD 2006). Displaces forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Seedlings are not very competitive in vigorous pasture. Can form dense stands on moist sites, choking out native vegetation (ESC NSW). Displaces understorey in forests and forages in pasture and prevents re-establishment of native species (Motooka et al 2003). Some change, but no serious alteration of agricultural return. Affects more visual rather than intrinsic agricultural value.	ML	M
23. Increase harvest costs?	May be controlled by slashing, followed by ripping or ploughing, then sowing a desirable pasture species (Motooka et al. 2003). Control is best achieved by good pasture management and timely herbicide use (Land Protection QLD 2006). Minor increase in cost of harvesting e.g. slightly more time or labour is required.	MH	M
24. Disease host/vector?	No mention of disease host in literature, presumably no host.	L	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Crofton weed can germinate during wet summer periods (Land Protection QLD 2006). Seeds can germinate nearly year round under favourable conditions. (DiTomaso & Healy 2007). [After fire] seeds germinate readily (Slotwinski 2002) Requires natural seasonal disturbances for germination.	MH	M
2. Establishment requirements?	It is frequently associated with shaded, wet areas fringing forests (including rainforest). (Land Protection QLD 2006). Can establish under moderate canopy/litter cover.	MH	M
3. How much disturbance is required?	Crofton weed invades pastures, colonises roadsides and forest edges. It is frequently associated with shaded, wet areas fringing forests (including rainforest) and along streams. It is also found as a weed on roadsides and overgrazed pastures (Land Protection QLD 2006). ‘It is a weed of roadsides, railway embankments, riverbanks and commercial timber plantations’ (Kluge 1991). Capable of infesting intact bushland and displacing native plants (WBM undated). Establishes in relatively intact or only minor disturbed natural ecosystems (e.g. wetlands, riparian, riverine, grasslands, open woodlands); in vigorously growing crops or well established pastures.	MH	MH
Growth/Competitive
4. Life form?	Perennial scrambling shrub (Kluge 1991). Other.	L	MH
5. Allelopathic properties?	Many native ecosystems have been modified due to allelopathic characteristics of this plant (Gu et al. 2008). Allelopathic properties seriously affecting some plants.	MH	MH
6. Tolerates herb pressure?	Unpalatable to cattle and poisonous to horses, other stock eats it without ill effect. (Motooka et al 2003; ESC NSW undated) Consumed but not preferred.	MH	M
7. Normal growth rate?	Fast growth rate (Gu et al. 2008). Crofton weed can germinate during wet summer periods and develops into good sized plants within twelve weeks, to flower the following spring (Land Protection QLD 2006) Moderately rapid growth rate that will equal competitive species of the same life form.	MH	ML
8. Stress tolerance to frost, drought, w/logg, sal. etc?	‘Most of the A. adenophora in South Africa occurs in moist habitats’ (Kluge 1991). Seedlings tolerate light shade (DiTomaso & Healy 2007). Persistent weed of high rainfall areas. Tolerant of wet soils and will extend to wetlands (Parsons and Cuthbertson 2001). Frost resistant but drought tender (Bodkin 1986). Occurs along creek beds, forest clearings and in areas with steep frost-free slopes where rainfall exceeds 1500 mm annually, also common on damp soils but is able to grow in shade or full sun (Slotwinski 2002). Crofton weed prefers sheltered, moist, nutrient-rich conditions (WBM undated). ‘After low intensity fires the plant re-shoots from the base…the plant overall does not burn easily’ Tolerant of at least two, susceptible to at least one.	ML	ML
Reproduction
9. Reproductive system	‘Reproduces primarily by seed’ ‘most vegetative growth occurs in summer and autumn’ (DiTomaso & Healy 2007). Both sexual and vegetative reproduction.	H	MH
10. Number of propagules produced?	Prolific seeders (Motooka et al. 2003). Abundant seeds (DiTomaso & Healy 2007). Seasoning in summer one plant can produce 10,000-100,000 [seeds] per year (Slotwinski 2002). Above 2000.	H	MH
11. Propagule longevity?	Unknown.	M	L
12. Reproductive period?	Perennial (Kluge 1991). Mature plant produces viable propagules for 3-10 years.	MH	M
13. Time to reproductive maturity?	Crofton weed can germinate during wet summer periods and develops into good sized plants within twelve weeks, to flower the following spring (Land Protection QLD 2006). ‘If damaged seedlings can regrow from the crown by 8 weeks of age’ (DiTomaso & Healy 2007). Seedlings grow rapidly and are fully established and able to regenerate from the crown, if damaged within 8 weeks of germination (Parsons and Cuthbertson 2001). Reaches maturity and produces viable propagules or vegetative propagules become separate individuals in under a year.	H	M
Dispersal
14. Number of mechanisms?	Wind blown seeds (Land Protection QLD 2006). Seeds disperse with wind, water, soil movement, human activities and by clinging to animals (DiTomaso & Healy 2007; Slotwinski 2002). Propagules spread by wind, water, attachment (humans, animals, vehicles) or by accidental human dispersal.	MH	M
15. How far do they disperse?	Wind blown seeds (Land Protection QLD 2006). Few propagules will disperse greater than one kilometre but many will reach 200-1000 metres.	MH	M

References

Agfacts http://www.bellingerlandcare.org.au/documents/Weed%20control/Agfacts/Crofton%20Weed.pdf

Bodkin F. (1986) Encyclopaedia Botanica: The Essential Reference Guide to Native and Exotic Plants in Australia. Angus & Robertson.

DiTomaso J, Healy E (2007) Weeds of California and other Western States: Aizoaceae-Fabaceae. Published by Regents of the University of California.

ESC NSW (undated) Eurobodalla Shire Council Weed Sheets. Available at http://www.esc.nsw.gov.au/site/Weeds/Sheets/herbs/H%20Crofton%20weed%20&%20mistflower.htm (verified 24 September 2009).

Gu W, Sang W, Liang H, Axmacher JC (2008) Effects of Crofton Weed Ageratina adenophora on assemblages of Caribidae (Coleoptera) in the Yunnan Province, South China. Agriculture, Ecosystems and Environment. 24 173-178.

Kluge RL (1991) Biological Control of crofton weed, Ageratina adenophora in South Africa. Agriculture Ecosystems and Environment 37 187-191

Land Protection (2006) Queensland Government Natural Resources and Water. PDF available at http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPACrofton-Weed-PP16.pdf (verified 24 September 2009).

Motooka P (2003) Weeds of Hawaii’s pastures and natural areas; an identification and management guide. College of tropical Agriculture and Human Resources University of Hawaii

Parsons WT and Cuthbertson EG. (2001) Noxious Weeds of Australia. 2nd Ed. CSIRO Publishing, Collingwood.

Slotwinski A (2002) Crofton Weed. PDF available http://www.wyong.nsw.gov.au/environment/Weeds_category_four_Crofton_Weed3.pdf (verified 24 September 2009).

South East Weeds (undated) http://www.southeastweeds.org.au/index.pl?page=131

WBM (undated) Weeds of the Blue Mountains Weed Information, available at http://www.weedsbluemountains.org.au/crofton_weed.asp (verified 24 September 2009).

Global present distribution data references

Australian National Herbarium (ANH) (2009) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at http://www.anbg.gov.au/avh/ (verified 19 November 2009).

Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 19 November 2009).

Global Biodiversity Information Facility (GBIF) (2009) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 19 November 2009).

Integrated Taxonomic Information System. (2009) Available at http://www.itis.gov/ (verified 19 November 2009).

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (verified 19 November 2009).

Royal Botanic Gardens Melbourne. (2009) Census of Vascular Plants of Victoria. Available at http://www.rbg.vic.gov.au/research_and_conservation/plant_information/viclist (verified 19 November 2009).

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2009) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 19 November 2009).

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