Creeping willow herb (Epilobium nummulariifolium)

Present distribution

Scientific name:	Epilobium nummulariifolium A. Cunn.
Common name(s):	creeping willow herb

This weed is not known to be naturalised in Victoria

Habitat:

Cliffs, banks, rocky and stony riverbeds, coastal slopes, talus, also along roadsides, railways and street gutters, waste places in and around habitations, gardens, sea level to 300-(900)m (Webb et al. 1988).

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:
horticulture perennial; horticulture seasonal; pasture irrigation

Ecological Vegetation Divisions
Coastal; swampy scrub; lowland forest; riparian; granitic hillslopes; rocky outcrop shrubland; alluvial plains grassland; semi-arid woodland; alluvial plains woodland; riverine woodland/forest;

Colours indicate possibility of Epilobium nummulariifolium 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 epilobium nummulariifolium

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Creeper…..“Individual plants can spread to form 1m diameter patches” (DPIW 2008). “Loosely matted” (SI 2008). Low growing creeping habit (see photos NZPCN 2008; DPIW 2008). L – Minimal or negligible impact (ie. can go anywhere).	L	MH
2. Reduce tourism?	Creeper…..“Individual plants can spread to form 1m diameter patches” (DPIW 2008). “Loosely matted” (SI 2008). Low growing creeping habit (see photos NZPCN 2008; DPIW 2008). Natural habitats tend toward harsh and include bare, typically moist substrate on cliff, banks, stony river beds, coastal slopes and talus. It is also a weed of roadsides, foot paths and untended places and especially troublesome in domestic gardens, lawns, glasshouses and among pot plants (DPIW 2008). ML- Minor effects to aesthetics and recreational uses (ie. aware but not bothered or activity inhibited).	ML	MH
3. Injurious to people?	No reports in the literature, unlikely as has no thorns burrs (pers. Obs). Low growing creeping habit (see photos NZPCN 2008; DPIW 2008). L – No effect, no prickles, no injuries.	L	MH
4. Damage to cultural sites?	Natural habitats tend toward harsh and include bare, typically moist substrate on cliff, banks, stony river beds, coastal slopes and talus. It is also a weed of roadsides, foot paths and untended places and especially troublesome in domestic gardens, lawns, glasshouses and among pot plants (DPIW 2008). Fibrous roots (Roy et al. 2004) unlikely to cause structural damage. ML- Moderate visual effect.	ML	MH
Abiotic
5. Impact flow?	Creeper…..“Individual plants can spread to form 1m diameter patches” (DPIW 2008). Forms dense patches (Richardson et al. 2006). Stony river beds (DPIW 2008). ML – Minor impact on surface or subsurface flow either by roots or free floating aquatics.	ML	M
6. Impact water quality?	Creeper…..“Individual plants can spread to form 1m diameter patches” (DPIW 2008). Forms dense patches (Richardson et al. 2006). Stony river beds (DPIW 2008). May reduce light levels. ML - Noticeable but minor effects in either dissolved oxygen or light levels.	ML	MH
7. Increase soil erosion?	“…reduced to dry leaves and stems above ground. The root system appeared healthy. This suggests that drying out is a coping mechanism” (Weed Alerts 2003). Roots fibrous (Roy et al. 2004). on cliff, banks, coastal slopes (DPIW 2008) “become a serious weed in gardens” (Roy et al. 2004) – implies perssitance. Likely to decrease the probability of soil movement. L- Low probability of large scale soil movement; or decreases the probability of soil erosion.	L	MH
8. Reduce biomass?	Forms dense patches (Richardson et al. 2006). Grows in disturbed bare areas (DPIW 2008) but has potential to cause problems in natural areas including upland areas where moisture is not limited. (Weed Alerts 2003). No info on reducing biomass. As it grows in mostly bare harsh conditions biomass is likely to increase or be the same. ML – Direct replacement of biomass by invader.	ML	M
9. Change fire regime?	“Heavy infestations of early December had reduced to dried leaves and stems above ground. The root system appeared healthy. This suggests that drying out is a coping mechanism” (Weed Alerts 2003). Therefore could provide fuel for fires in the dry months. Not enough information in literature.	MH	L
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Riparian Scrub (E); CMA = Glenelg Hopkins; Bioregion =Victorian Volcanic Plain; H CLIMATE potential. “it may have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008)” “plant could establish and exert negative impacts in areas of Tasmania where moisture is not limited including upland areas” (Weed Alerts 2003).	MH	MH
(b) medium value EVC	EVC = Riparian Scrub (D); CMA =CORANGAMITE; Bioregion =Otway plain; H CLIMATE potential. “it may have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008)” “plant could establish and exert negative impacts in areas of Tasmania where moisture is not limited including upland areas” (Weed Alerts 2003).	MH	MH
(c) low value EVC	EVC = Coastal Headland Scrub (LC); CMA =East Gippsland; Bioregion =East Gippsland Lowlands; H CLIMATE potential. “it may have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008)” “plant could establish and exert negative impacts in areas of Tasmania where moisture is not limited including upland areas” (Weed Alerts 2003).	MH	MH
11. Impact on structure?	“Weed risk assessment indicated that the plant could establish and exert negative impacts in areas of Tasmania where moisture is not limited including upland areas” (Weed Alerts 2003). Natural habitats tend toward harsh and include bare, typically moist substrate on cliff, banks, stony river beds, coastal slopes and talus. It is also a weed of roadsides, foot paths and untended places and especially troublesome in domestic gardens, lawns, glasshouses and among pot plants (DPIW 2008). ML – Minor effect on 20-60% of the floral strata.	ML	M
12. Effect on threatened flora?	“The conservation threat posed by this plant is not likely to be large, however it may have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008)”. MH- Any population of Bioregional Priority 1A* spp is reduced, or any population of a VROT spp is replaced.	MH	M
Fauna
13. Effect on threatened fauna?	Plant-species interactions not mentioned in the literature for E. nummulariifolium, No mention of toxins, no spines or burrs (DPIW 2008). May have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008). Minor probability of changing habitat/ food availability of threatened fauna. ML – Minor effects on threatened	ML	M
14. Effect on non-threatened fauna?	Plant-species interactions not mentioned in the literature for E. nummulariifolium, No mention of toxins, no spines or burrs (DPIW 2008). May have serious local effects if allowed to establish in disturbed areas within or near vegetation communities hosting threatened herbaceous species” (DPIW 2008). Minor probability of changing habitat/ food availability of threatened fauna. ML – Minor effects on threatened	ML	M
15. Benefits fauna?	Not listed as palatable in literature (Pers. Obs). Does not produce fleshy fruit (NZPCN 2008), low growing creeper (DPIW 2008) unlikely to provide shelter. Unlikely to benefit fauna. H- provides very little support to desirable species.	H	M
16. Injurious to fauna?	Plant-species interactions not mentioned in the literature for E. nummulariifolium, No mention of toxins, no spines or burrs (DPIW 2008). Unlikely to be injurious to fauna as it is a serious weed in New Zealand (Roy et al. 2004) but no mention of it having ill effects on animals. L- no effect.	L	M
Pest Animal
17. Food source to pests?	Not listed as palatable in literature (Pers. Obs). Does not produce fleshy fruit (NZPCN 2008). Not enough information. M-	M	L
18. Provides harbor?	Low growing creeper – unlikely to provide harbour. L – No harbour for pest species.	L	M
Agriculture
19. Impact yield?	“It may, like its weed relative E. ciliatum, add to the weed burden of pome and stone fruit growers” (DPIW 2008). “This plant is likely to cause problems for the nursery industry where it could become a significant pot and propagation bed contaminant…..despite frequent cultivation, had persisted for several years” (Weed Alerts 2003). Possible negative effects on quantity of produce in orchards and nurseries. M	M	M
20. Impact quality?	“It may, like its weed relative E. ciliatum, add to the weed burden of pome and stone fruit growers” (DPIW 2008). “This plant is likely to cause problems for the nursery industry where it could become a significant pot and propagation bed contaminant…..despite frequent cultivation, had persisted for several years” (Weed Alerts 2003). Possible negative effects on quality of produce in orchards and nurseries. M	M	M
21. Affect land value?	“It may, like its weed relative E. ciliatum, add to the weed burden of pome and stone fruit growers” (DPIW 2008). “This plant is likely to cause problems for the nursery industry where it could become a significant pot and propagation bed contaminant…..despite frequent cultivation, had persisted for several years in a nursery, which has subsequently closed down (Weed Alerts 2003). ML- decreases in land value <10%	ML	M
22. Change land use?	“It may, like its weed relative E. ciliatum, add to the weed burden of pome and stone fruit growers” (DPIW 2008). “This plant is likely to cause problems for the nursery industry where it could become a significant pot and propagation bed contaminant…..despite frequent cultivation, had persisted for several years” (Weed Alerts 2003). From what is written about this species in the literature it is unlikely that this species would be solely responsible for causing a change in land use. L- Little or no change	L	M
23. Increase harvest costs?	“It may, like its weed relative E. ciliatum, add to the weed burden of pome and stone fruit growers” (DPIW 2008). “This plant is likely to cause problems for the nursery industry where it could become a significant pot and propagation bed contaminant…..despite frequent cultivation, had persisted for several years” (Weed Alerts 2003). As this weed is persistent, constant control would be required and this would increase harvest costs. – especially in nursery trade. MH- minor increase in cost of harvesting.	MH	M
24. Disease host/vector?	No information in the literature (pers. Obs). M	M	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Cliffs, banks, rocky and stony riverbeds, coastal slopes, talus, also along roadsides, railways and street gutters, waste places in and around habitations, gardens, sea level to 300-(900)m (Webb et al. 1988). Where moisture is not limited (Weed Alerts 2003). “Where well illuminated” (SI 2008). MH- Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination.	MH	M
2. Establishment requirements?	Cliffs, banks, rocky and stony riverbeds, coastal slopes, talus, also along roadsides, railways and street gutters, waste places in and around habitations, gardens, sea level to 300-(900)m (Webb et al. 1988). Suggested spread is a result of human activities, grows in very modified habitats and is often a serious weed in gardens, particularly in rock gardens, glass houses and amongst pot plants (Webb et al. 1988). Where moisture is not limited (Weed Alerts 2003). “Where well illuminated” (SI 2008). ML- Requires more specific requirements to establish (eg. Open space or bare ground with access to light and direct rainfall).	ML	MH
3. How much disturbance is required?	Cliffs, banks, rocky and stony riverbeds, coastal slopes, talus, also along roadsides, railways and street gutters, waste places in and around habitations, gardens, sea level to 300-(900)m (Webb et al. 1988). Suggested spread is a result of human activities, grows in very modified habitats and is often a serious weed in gardens, particularly in rock gardens, glass houses and amongst pot plants (Webb et al. 1988). ML – Establishes in highly disturbed natural ecosystems (eg. Roadsides, wildlife corridors, or areas which have a greater impact by by humans such as tourist areas or campsites) or in overgrazed pastures/poorly growing or patchy crops.	ML	MH
Growth/Competitive
4. Life form?	Loosely matted, creeping, stem rooting herb forming patches up to 1m across (Webb et al. 1988). L – other.	L	MH
5. Allelopathic properties?	None mentioned in the literature. M.	M	L
6. Tolerates herb pressure?	No info in the literature. M	M	L
7. Normal growth rate?	No info in the literature. M	M	L
8. Stress tolerance to frost, drought, w/logg, sal. etc?	stony riverbeds (Webb et al. 1988) so possibly tolerant to waterlogging. “Where well illuminated” (SI 2008) probably not shade tolerant. Coastal slopes (Webb et al. 1988) tolerant to salinity. “…reduced to dry leaves and stems above ground. The root system appeared healthy. This suggests that drying out is a coping mechanism” (Weed Alerts 2003). ML- Tolerant to at least two and susceptible to at least one.	ML	M
Reproduction
9. Reproductive system	Reproduction is via seeds but the plant may also root from stem nodes (DPIW 2008). H – Both vegetative and sexual reproduction (Vegetative reproduction may be via cultivation, but not propagation).	H	MH
10. Number of propagules produced?	Fruit are thin, hairy pods that grow to 4cm at the end of conspicuous flower stalks which can reach 12.5cm long (DPIW 2008). Numerous flowers (SI 2008) and approx 100 seeds per flower (see photo NZPCN 2008). 1000-2000 or more seeds. MH 1000-2000.	MH	M
11. Propagule longevity?	Soil contaminant – “creeping willow herb has been a problem at the site of his business for 5 or 6 years” (Weed Alerts 2003). Not enough info - M	M	L
12. Reproductive period?	“Perennial” (DPIW 2008). MH – 3-10years.	MH	M
13. Time to reproductive maturity?	No info in the literature. M	M	L
Dispersal
14. Number of mechanisms?	“Spread results from its creeping habit and the dispersal of its seeds around the parent or in contaminated soil, potting media and the like. Distribution of seed-pods in water is also possible (DPIW 2008).Wind born seed (Weed Alerts 2003). Very light (see photo NZPCN 2008). H- Very light, wind dispersed seeds, OR bird dispersed seeds, OR has edible fruit that is readily eaten by highly mobile animals.	H	MH
15. How far do they disperse?	0.7-1mm long, 0.2-0.4mm wide (SI 2008). Dispersal of its seeds around the parent, distribution of seed-pods in water is also possible (DPIW 2008). “No other creeping willow herb plants were found in the vicinity. It seems likely that this infestation has arisen from wind-bourne seed” (Weed Alerts 2003). H -	H	MH

References

DPIW (2008) Department of Primary Industries and Water – Tasmania. Creeping Willow Herb Weed Bulletin. www.dpiw.tas.gov.au (25/11/2008).

NZPCN (2008) New Zealand Plant Conservation Network. http://images.google.com.au/imgres?imgurl=http://www.nzpcn.org.nz/imgs/threatenedplants/70x70/Epilobiumnummulariifoli-04.jpg&imgrefurl=http://www.nzpcn.org.nz/vascular_plants/index02.asp%3FFilter%3De%26FilterStatus%3D12&usg=__z7PfIyB7U2qQ34O0DuXy1wFwNx4=&h=70&w=70&sz=5&hl=en&start=3&um=1&tbnid=5GReYjauG8-WZM:&tbnh=68&tbnw=68&prev=/images%3Fq%3DEpilobium%2Bnummulariifolium%26um%3D1%26hl%3Den (verified 27/11/2008).

SI (2008) Smithsonian Institute – Epilobium nummariifolium. http://botany.si.edu?onagraceae/speciesdescr.cfm?myID=4255 (verified 25/11/2008).

Richardson, F.J., Richardson, R.G. and Shepherd, R.C.H. (2006). Weeds of the South-East. An identification guide for Australia. R.G. & F.J. Richardson. Meredith, Victoria.
ISBN 0958743932, 438 pages.

Roy, B., Popay, I., Champion, P., James, T. & Rahman, A. (2004) An Illustrated Guide to Common Weeds of New Zealand 2nd Edition. New Zealand Plant Protection Society.

Weed Alert (2003). Weed Alert – Tasmania. Epilobium update. Tasweeds incorporating Spotter. Edition 18 March 2003 p14.

Webb, C. J., W. R. Sykes, and P. J. Garnock-Jones (1988) Flora of New Zealand vol. 4. Published by Botany Division, DSIR, Christchurch, New Zealand.

Global present distribution data references

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at
http://www.anbg.gov.au/avh/ (verified 10/11/08).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 10/11/08).

Missouri Botanical Gardens (MBG) (2008) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (verified
10/11/08).

National Biodiversity Network (2004) NBN Gateway, National Biodiversity Network, UK, Available at http://www.searchnbn.net/index_homepage/index.jsp (verified
10/11/08).

Feedback

Do you have additional information about this plant that will improve the quality of the assessment?
If so, we would value your contribution. Click on the link to go to the feedback form.

Page top