Rosy watsonia (Watsonia borbonica)

Present distribution

Scientific name:	Watsonia borbonica (Pourr.) Goldblatt.
Common name(s):	rosy watsonia

This weed is not known to be naturalised in Victoria

Habitat:

Sandy soils, sandy clays gravelly sand, granites. Hills and flats, riverbanks and lake edges, road verges (Spooner 2007). Can be found on rocky sandstone slopes, on granite and clay at various elevations (Pacific Bulb Society; Manning and Paterson-Jones 2008). Common on mountain slopes (Fernkloof undated). “Sunny well drained position which is fairly dry over summer” (iGarden 2009). Drought tolerant (Dave’s Garden undated). “It can withstand a mild winter frost” (Nonkenge and Notten 2005).

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; forestry; horticulture perennial; horticulture seasonal; pasture dryland; pasture irrigation; water

Ecological Vegetation Divisions
Coastal; heathland; grassy/heathy dry forest; lowland forest; foothills forest; forby forest; damp forest; riparian; wet forest; high altitude shrubland/woodland; high altitude wetland; alpine treeless; granitic hillslopes; rocky outcrop shrubland; alluvial plains woodland; ironbark/box; riverine woodland/forest;

Colours indicate possibility of Watsonia borbonica 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 watsonia borbonica

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	1.5-2.5 metres high (Spooner 2007). Grows along riverbanks and lake edges (Spooner 2007). - Low nuisance value, impedes individual access; unable to walk to waterways.	ML	M
2. Reduce tourism?	1.5-2.5 metres high. Grows along riverbanks and lake edges. “In South Africa it has been noted Watsonia borbonica is particularly abundant after fire and is known at some sites to only flower in the first and second years following fire. The increased flowering post fire is followed by prolific seed production.” (Spooner 2007). - Minor effects to aesthetics and/or recreational uses (i.e. aware of but not bothered).	ML	M
3. Injurious to people?	No evidence of injurious characteristics. -None.	L	ML
4. Damage to cultural sites?	1.5-2.5 metres high (Harden 1993; Spooner 2007). Grows along riverbanks and lake edges. “In South Africa it has been noted Watsonia borbonica is particularly abundant after fire and is known at some sites to only flower in the first and second years following fire. The increased flowering post fire is followed by prolific seed production.” (Spooner 2007). - Moderate visual effect.	ML	M
Abiotic
5. Impact flow?	Grows along riverbanks and lake edges (Spooner 2007) but is not an aquatic species; therefore unlikely to impact on water flow. - Negligible impact on water flows.	L	M
6. Impact water quality?	Grows along riverbanks and lake edges (Spooner 2007), but not an aquatic species, therefore unlikely to impact on water quality. - No noticeable effects to dissolved O2 or light levels.	L	M
7. Increase soil erosion?	1.5-2.5 metres high (Harden 1993; Spooner 2007). Grows along riverbanks and lake edges (Spooner 2007). “Stems sturdy, usually several-branched (Fernkloof undated). Cormous perennial. Its habitat is mainly rocky sandstone slopes or well drained slopes of clay and granite, and sometimes in deep sandy soil at the foot of the mountains. (Nonkenge and Notten 2005). - Moderate probability of large scale soil erosion.	ML	M
8. Reduce biomass?	The increased flowering post fire is followed by prolific seed production. Grows 1.5-2.5 metres high (Harden 1993; Spooner 2007). Not enough information.	M	L
9. Change fire regime?	“In South Africa it has been noted Watsonia borbonica is particularly abundant after fire and is known at some sites to only flower in the first and second years following fire. The increased flowering post fire is followed by prolific seed production.” (Spooner 2007). Little evidence that Watsonia borbonica will alter the fire regime in any way.	L	M
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Floodplain riparian woodland (V); CMA = Glenelg Hopkins; Bioregion = Dundas Tablelands; VH CLIMATE potential. Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands, roadsides along riverbanks and lake edges (Harden 1993; Spooner 2007). - Very little displacement of any indigenous species. Sparse or scattered infestations.	L	H
(b) medium value EVC	EVC = Herb Rich Foothills Forest (D); CMA = Goulburn Broken; Bioregion = Central Victorian Uplands; VH CLIMATE potential. Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands, roadsides along riverbanks and lake edges (Harden 1993; Spooner 2007). - Minor displacement of some dominant or indicator species within any one strata/layer.	ML	H
(c) low value EVC	EVC = Wet Heathland (LC); CMA = West Gippsland; Bioregion = Wilson’s Promontory; VH CLIMATE potential. Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands, roadsides along riverbanks and lake edges (Harden 1993; Spooner 2007). - Very little displacement of any indigenous species. Sparse or scattered infestations.	L	H
11. Impact on structure?	Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands, roadsides along riverbanks and lake edges (Harden 1993; Spooner 2007). - Minor effects on 20-60% of the floral strata.	ML	MH
12. Effect on threatened flora?	Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Harden 1993; Spooner 2007). Impacts on threatened flora are undetermined.	MH	L
Fauna
13. Effect on threatened fauna?	Grows 1.5-2.5 metres high (Harden 1993; Spooner 2007). In areas that have burnt, Watsonia borbonica provides a major source of food for nectar-feeding insects and birds, and for various rodents…” (Nonkenge and Notten 2005). Impacts on threatened fauna are undetermined.	MH	L
14. Effect on non-threatened fauna?	Grows 1.5-2.5 metres high (Harden 1993; Spooner 2007). In areas that have burnt, Watsonia borbonica provides a major source of food for nectar-feeding insects and birds, and for various rodents…” (Nonkenge and Notten 2005). No fauna affected due to fauna not co-existing within weed area or strata.	L	M
15. Benefits fauna?	Grows 1.5-2.5 metres high (Harden 1993; Spooner 2007). In areas that have burnt, Watsonia borbonica provides a major source of food for nectar-feeding insects and birds, and for various rodents…” (Nonkenge and Notten 2005). - Provides some assistance in either food or shelter for desirable species.	MH	M
16. Injurious to fauna?	No evidence of injurious characteristics. - No effect.	L	ML
Pest Animal
17. Food source to pests?	“In areas that have burnt, Watsonia borbonica provides a major source of food for nectar-feeding insects and birds, and for various rodents…” (Nonkenge and Notten 2005). May potentially provide some food for serious pest species. - Supplies food for one or more minor pest species.	ML	M
18. Provides harbour?	Grows 1.5-2.5 metres high amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Harden 1993; Spooner 2007). Size of Watsonia borbonica at maturity may provide some shelter. - Doesn’t provide shelter for serious pest species, may provide for minor pests.	ML	M
Agriculture
19. Impact yield?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Watsonia borbonica is not known to be an agricultural weed, therefore unlikely to impact yields. - Little or negligible affect on quantity of yield.	L	M
20. Impact quality?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Watsonia borbonica is not known to be an agricultural weed, therefore unlikely to impact quality. - Little or negligible impacts on quality of yield.	L	M
21. Affect land value?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Watsonia borbonica is not known to be an agricultural weed, therefore unlikely to alter value of land. - Little or none.	L	M
22. Change land use?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Watsonia borbonica is not known to be an agricultural weed, therefore unlikely to change land uses. - Little or no change.	L	M
23. Increase harvest costs?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Watsonia borbonica is not known to be an agricultural weed, therefore unlikely to increase harvesting costs. - Little or no cost.	L	M
24. Disease host/vector?	No serious disease problems (Missouri Botanical Garden 2001-2009). Not listed on Plant Viruses Online (Brunt et al. - Little or no host.	L	M

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Corms are dormant from summer through to autumn (Dec-April) in South Africa. Seed is sown in autumn, and germinate readily in 3-4 weeks. (Nonkenge and Notten 2005). - Requires natural seasonal disturbances, such as seasonal rainfall and temperatures to germinate.	MH	M
2. Establishment requirements?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). Appears to be able to establish under some shade. - Requires more specific requirements to establish (e.g. bare ground, open space).	ML	M
3. How much disturbance is required?	Habitats include amongst medium trees, low sclerophyll shrub land, grasslands and roadsides (Spooner 2007). - Establishes in relatively intact or only minor disturbed natural ecosystems.	MH	M
Growth/Competitive
4. Life form?	Geophyte (Spooner 2007).	ML	M
5. Allelopathic properties?	No evidence of allellopathy (Rice 1984). - None.	L	MH
6. Tolerates herb pressure?	Unknown.	M	L
7. Normal growth rate?	Unknown.	M	L
8. Stress tolerance to frost, drought, w/logg, sal. etc?	“Sunny well drained position which is fairly dry over summer” (iGarden 2009). Drought tolerant (Dave’s Garden undated). “It can withstand a mild winter frost” (Nonkenge and Notten 2005). Best grown where there is little or no frost (Backyard Gardener undated). - Tolerant of at least two and susceptible to at least one.	ML	ML
Reproduction
9. Reproductive system	Reproduction - Offsets, possibly seed (Spooner 2007). The easiest method of propagation is via division (Nonkenge and Notten 2005). - Evidence of both sexual and vegetative reproduction	H	M
10. Number of propagules produced?	Unknown.	M	L
11. Propagule longevity?	Seed bank persistence - medium 1-5 years (Spooner 2007). “The corms can remain dormant for many years” (Weeds Australia undated) - Greater than 25% of seeds survive 5 years or vegetatively reproduces.	L	M
12. Reproductive period?	Perennial (Nonkenge and Notten 2005). - Mature plant produces viable propagules for 3-10 years.	MH	M
13. Time to reproductive maturity?	Time to first flowering - 2-3 years (Spooner 2007). - Two to five years to reach sexual maturity, or vegetative propagules become separate individuals.	ML	M
Dispersal
14. Number of mechanisms?	Dispersal - Wind, water, soil. (Spooner 2007). - Propagules spread by wind and water or accidental human dispersal (through soil).	MH	M
15. How far do they disperse?	Dispersal - Wind, water, soil. (Spooner 2007). - Few propagules will disperse greater than one kilometre; many will reach 200-1000 metres.	MH	M

References

Backyard Gardener (undated) available at http://www.backyardgardener.com/plantname/pda_1d5c.html (verified 07 May 2009).

Brunt AA, Crabtree K, Dallwitz MJ, Gibbs AJ, Watson L, Zurcher EJ (eds.) (1996 onwards) Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version 20th August 1996. Available at http://biology.anu.edu.au/Groups/MES/vide/ (verified 05 May 2009).

Dave’s Garden (undated). Available at http://davesgarden.com/guides/pf/go/65246/ (verified 07 May 2009).

Fernkloof Nature Reserve (undated) http://fernkloof.com/species2.mv?Watsonia%20borbonica (verified 07 May 2009).

Harden GJ. (1993) Flora of New South Wales. Volume 4. Royal Botanic Gardens Sydney, UNSW Press

iGarden (2009). Available at http://www.igarden.com.au/plant-type.jsp?id=37&t=Watsonia (verified 07 May 2009).

Manning J and Paterson-Jones C (2008) Field Guide to Fynbos. Struik Publishing.

Nonkenge S and Notten A (2005). Watsonia borbonica (Pourr.) Goldblatt. Kirstenbosch National Botanical Garden. Available at
http://www.plantzafrica.com/plantwxyz/watsonborb.htm (verified 07 May 2009).

Pacific Bulb Society (2009) Watsonia. Available at http://www.pacificbulbsociety.org/pbswiki/index.php/Watsonia (verified 07 May 2009).

Rice EL. (1984) Allelopathy. Academic Press, Inc. Orlando.

Spooner A, Carpenter J, Smith G, Spence K (2007) Watsonia borbonica (Pourr.) Goldblatt in FloraBase the Western Australian Flora. Available at
http://florabase.calm.wa.gov.au/browse/profile/13103 (verified 07 May 2009).

Weeds Australia Weed Identification (undated). Available at http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&ibra=all&card=E51 (verified 07 May 2009).

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 05 May 2009).

Calflora: Information on California plants for education, research and conservation. [web application]. (2008) Berkeley, California: The Calflora Database [a non-profit organization]. Available at http://www.calflora.org/ (verified 05 May 2009).

Den virtuella floran (DVF) (2009) Naturhistoriska riksmuseet, Available at http://linnaeus.nrm.se/flora/ (verified 05 May 2009).

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) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 05 May 2009).

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

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html(verified 05 May 2009).

National Biodiversity Network (2004) NBN Gateway, National Biodiversity Network, UK, Available at http://www.searchnbn.net/index_homepage/index.jsp (verified 05 May 2009).

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