Grey sedge (Carex divulsa)

Present distribution

Scientific name:	Carex divulsa Stokes.
Common name(s):	grey sedge

Map showing the present distribution of this weed.

Habitat:

Native to Europe, except in the far north, in grassy areas, often shaded; dry places on alkaline soils; and a weed in grasslands in New Zealand (Simpson & Inglis 2001). Occurs in Hyrcanain forest, on forest floor and in glades and meadow, probably also in dry, rocky habitats [Persia] (Kukkonen 1998). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). ‘Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins+ and readily adapt to similar situations in the garden (RHS 1994).‘An excellent, very tough ground cover for shade (or sun), thriving under trees’ (Annie’s Annuals 2009). ‘Can grow in full sun to full shade and in most any soil’ (Fine Gardening). It is a very versatile plant for use in coastal, full sun to fairly deep shade, it tolerates boggy wet soils but is also fairly drought tolerant once established. (San Marcos 2001).

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; swampy scrub; freshwater wetland (permanent); treed swampy wetland; lowland forest; foothills forest; forby forest; damp forest; riparian; wet forest; rainforest; high altitude shrubland/woodland; high altitude wetland; alpine treeless; granitic hillslopes; rocky outcrop
shrubland; western plains woodland; basalt grassland; alluvial plains grassland; semi-arid woodland; alluvial plains woodland; ironbark/box; riverine woodland/forest; freshwater wetland (ephemeral); saline wetland; chenopod shrubland; chenopod mallee; hummock-grass mallee; lowan mallee; broombush whipstick

Colours indicate possibility of Carex divulsa 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 carex divulsa

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Tussocks up to 50cm across (David and Kelcey 1985). Clump-forming (Annie’s Annuals 2009). ‘Foliage forms an exceptionally dense, slow spreading clump 30-45cm tall (Darke 2007). Low nuisance value, impedes individual access; unable to walk to waterways.	ML	M
2. Reduce tourism?	Clump-forming (Annie’s Annuals 2009). A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Minor effects to aesthetics.	ML	M
3. Injurious to people?	Stem sharply trigonous with scabrous edges, but soft leaves (Kukkonen 1998). May cause minor irritation if pulled. No effect, no prickles, no injuries.	L	M
4. Damage to cultural sites?	Clump-forming (Annie’s Annuals 2009). A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Moderate structural effect.	MH	MH
Abiotic
5. Impact flow?	Grown around ponds (Spencer 2005). Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994). Little or negligible affect on water flow.	L	MH
6. Impact water quality?	Grown around ponds (Spencer 2005). Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994). No noticeable impacts on dissolved O₂, or light levels.	L	MH
7. Increase soil erosion?	‘Short rhizomes in the top 4cm of soil, the thicker roots reaching a depth of 1.25-2 metres’ (David and Kelcey 1985). Carex species are sometimes used as erosion control (Spencer 2005). Moderate probability of large scale soil movement.	ML	MH
8. Reduce biomass?	Insufficient information.	M	L
9. Change fire regime?	Insufficient information.	M	L
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Cool Temperate Rainforest (V); CMA = Corangamite; Bioregion = Otway Ranges; VH CLIMATE potential. ‘Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994).‘An excellent, very tough ground cover for shade (or sun), thriving under trees’ (Annie’s Annuals 2009). ‘It is a very versatile plant for use in coastal, full sun to fairly deep shade; it tolerates boggy wet soils but is also fairly drought tolerant once established. (San Marcos 2001). Minor displacement of some dominant or indicator species within any one layer/strata (e.g. ground cover, forbs, shrubs, trees etc.).	ML	H
(b) medium value EVC	EVC = Sub-alpine Woodlands (R); CMA = East Gippsland; Bioregion = Monaro Tablelands; VH CLIMATE potential. ‘Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994).‘An excellent, very tough ground cover for shade (or sun), thriving under trees’ (Annie’s Annuals 2009). ‘It is a very versatile plant for use in coastal, full sun to fairly deep shade; it tolerates boggy wet soils but is also fairly drought tolerant once established. (San Marcos 2001). Elevation 10-200m (Flora of North America undated). Very little displacement of any indigenous species. Sparse and scattered infestations.	L	H
(c) low value EVC	EVC = Seasonally Inundated Shrubby Woodland (LC); CMA = Wimmera; Bioregion = Lowan Mallee; VH CLIMATE potential. ‘Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994).‘An excellent, very tough ground cover for shade (or sun), thriving under trees’ (Annie’s Annuals 2009). ‘It is a very versatile plant for use in coastal, full sun to fairly deep shade; it tolerates boggy wet soils but is also fairly drought tolerant once established. (San Marcos 2001). Minor displacement of some dominant or indicator species within any one layer/strata (e.g. ground cover, forbs, shrubs, trees etc.).	ML	H
11. Impact on structure?	'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Tussocks up to 50cm across (David and Kelcey 1985). Clump-forming (Annie’s Annuals 2009). Minor displacement of some dominant or indicator species within one strata/layer (e.g. ground cover, forbs, shrubs & trees).	ML	MH
12. Effect on threatened flora?	'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Impacts on threatened flora are uncertain.	MH	L
Fauna
13. Effect on threatened fauna?	'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Used for cattle fodder in New Zealand (Simpson & Inglis 2001). Impacts on threatened fauna are uncertain.	MH	L
14. Effect on non-threatened fauna?	Clump-forming (Annie’s Annuals 2009). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed. Foliage has similar fodder value as grass (Spencer 2005). Used for cattle fodder in New Zealand (Simpson & Inglis 2001). Impacts on non-threatened fauna are unknown.	M	L
15. Benefits fauna?	Clump-forming (Annie’s Annuals 2009). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Provides very little assistance to desirable species.	H	M
16. Injurious to fauna?	No evidence of injurious characteristics.	L	L
Pest Animal
17. Food source to pests?	Foliage has similar fodder value as grass (Spencer 2005). Used for cattle fodder in New Zealand (Simpson & Inglis 2001). May supply food for serious pests, but at low levels.	MH	M
18. Provides harbor?	Clump-forming (Annie’s Annuals 2009). Carex have been grown for revegetation schemes used for wildlife habitat (Spencer 2005). Assumed that would provide habitat for minor species, but not major pests.	ML	M
Agriculture
19. Impact yield?	‘Carex divulsa is frequently found in hedgerows and in pastures and waste-ground…more often on basic soils.’ (Tutin & Jeremy 1968). ‘Fields, pastures, scrub, forest edges; 10-200m (Flora of North America undated). ‘Although fairly uncommon, can be troublesome in lawns, gardens and disturbed sites’ (Richardson et al. 2006). Used for cattle fodder in New Zealand (Simpson & Inglis 2001). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Little or negligible impacts on quantity of yield.	L	MH
20. Impact quality?	‘Carex divulsa is frequently found in hedgerows and in pastures and waste-ground…more often on basic soils.’ (Tutin & Jeremy 1968). ‘Fields, pastures, scrub, forest edges; 10-200m (Flora of North America undated). ‘Although fairly uncommon, can be troublesome in lawns, gardens and disturbed sites’ (Richardson et al. 2006). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Little or negligible affect on quality of yield.	L	MH
21. Affect land value?	‘Carex divulsa is frequently found in hedgerows and in pastures and waste-ground…more often on basic soils.’ (Tutin & Jeremy 1968). ‘Fields, pastures, scrub, forest edges; 10-200m (Flora of North America undated). ‘Although fairly uncommon, can be troublesome in lawns, gardens and disturbed sites’ (Richardson et al. 2006). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Little or none.	L	MH
22. Change land use?	‘Carex divulsa is frequently found in hedgerows and in pastures and waste-ground…more often on basic soils.’ (Tutin & Jeremy 1968). ‘Fields, pastures, scrub, forest edges; 10-200m (Flora of North America undated). ‘Although fairly uncommon, can be troublesome in lawns, gardens and disturbed sites’ (Richardson et al. 2006). 'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Little or no change.	L	MH
23. Increase harvest costs?	'A naturalised species from Europe, C. divulsa shows tendency to become locally prolific as potentially devastating environmental and agricultural weed (Spencer 2005). Insufficient information.	M	L
24. Disease host/vector?	Unknown.	M	L

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Propagates easily by seed or division in autumn or spring (Uni California 2009). Requires natural seasonal disturbances for germination.	MH	M
2. Establishment requirements?	‘An excellent, very tough ground cover for shade (or sun)., thriving under trees’ (Annie’s Annuals 2009). ‘Can grow in full sun to full shade and in most any soil’ (Fine Gardening undated). Can establish under moderate canopy/litter cover.	MH	M
3. How much disturbance is required?	‘Carex divulsa is frequently found in hedgerows and in pastures and waste-ground…more often on basic soils.’ (Tutin & Jeremy 1968). ‘Fields, pastures, scrub, forest edges; 10-200m (Flora of North America undated). ‘Although fairly uncommon, can be troublesome in lawns, gardens and disturbed sites’ (Richardson et al. 2006). ‘Many Carex inhabit damp woodlands, bogs, moors, ditches and water margins and readily adapt to similar situations in the garden (RHS 1994). Very adaptable and can grow in full sun to full shade and most any soil (Fine Gardening undated). Establishes in highly disturbed natural ecosystems (e.g. roadsides, wildlife corridors or areas which have a greater impact by humans such as tourist areas or campsites) or in overgrazed pastures/poorly growing crops.	MH	M
Growth/Competitive
4. Life form?	Caespitose from 15-60cm tall, forming small tufts with short stolons (Kukkonen 1998). ‘Carex species are grass-like herbs’ (Richardson et al. 2006). Grass/leguminous plant.	MH	MH
5. Allelopathic properties?	No evidence of allelopathy.	L	L
6. Tolerates herb pressure?	Foliage has similar fodder value as grass (Spencer 2005). Used for cattle fodder in New Zealand (Simpson & Inglis 2001). Insufficient information.	M	L
7. Normal growth rate?	Moderate growth rate (California Uni 2009). Growth rate equal to the same life form.	M	M
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Tolerant of dry conditions and poor soils (Richardson et al. 2006). ‘An excellent, very tough ground cover for shade (or sun), thriving under trees’ ‘Drought tolerant’ (Annie’s Annuals 2009). ‘Low water needs’ (San Marcos 2001). ‘Tolerates boggy soils but is also fairly drought tolerant once established’ ‘Inhabits the coast range of California north to British Columbia’ (San Marcos 2001). Elevation 10-200m (Flora of North America undated). Carex species require moist but well drained soils in full sun with some protection from harsh winds and prolonged frost (RHS 1994). ‘Drought tolerant once established’ (Darke 2007). Tolerant to at least two, susceptible to at least one.	ML	M
Reproduction
9. Reproductive system	Propagation easy by seed or division (Spencer 2005). Both vegetative and sexual reproduction.	H	M
10. Number of propagules produced?	Unknown.	M	L
11. Propagule longevity?	Unknown.	M	L
12. Reproductive period?	Perennial (Richardson et al. 2006). Mature plant produces viable propagules for 3-10 years	MH	MH
13. Time to reproductive maturity?	Perennial (Richardson et al. 2006). 2-5 years to reach reproductive maturity or for vegetative propagules to become separate individuals.	ML	M
Dispersal
14. Number of mechanisms?	Unknown.	M	L
15. How far do they disperse?	Unknown.	M	L

References

Annie’s Annuals (2009) Available at http://www.anniesannuals.com/plants/plant_display.asp?prodid=208 (verified 10 November 2009).

David RW and Kelcey JG (1985) Biological flora of the British Isles Fine gardening (undated) available at http://www.finegardening.com/plantguide/carex-divulsa-berkeley-sedge.aspx (verified 10 November 2009).

Flora of North America (undated) Carex available online at http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=105644 (verified 10 November 2009).

Jermy AC and Tutin TG (1968) British sedges: handbook to the species of Carex found growing on the British Isles. Botanical Society of the British Isles, London.

RHS (1994) Royal Horticultural Society Manual of Grasses. Published by Timber Press Inc. Portland, Oregon.

Richardson FJ, Richardson RG and Shepherd RCH. (2006) Weeds of the South-east. An Identification Guide for Australia. RG & FJ Richardson. Meredith.

San Marcos (2001). San Marcos Growers product information Carex divulsa. Available at http://www.smgrowers.com/products/plants/plantdisplay.asp?plant_id=352 (Verified 10 November 2009).

Spencer R. (Ed.) (2005) Horticultural Flora of South-Eastern Australia Volume 5. Flowering Plants Monocotyledons. UNSW Press.

Uni California (2009). Carex divulsa (formally Carex tumicola). Available at http://ucce.ucdavis.edu/datastore/datastoreview/showpage.cfm?usernumber=54&surveynumber=451 (Verified 10 November 2009).

Wilson K (2006). PlantNet file Carex divulsa Gooden. Available online at http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Carex~divulsa (verified 20 November 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 10 November 2009).

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

Global Biodiversity Information Facility (GBIF) (2009) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 10 November 2009).

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (verified 10 November 2009).

National Biodiversity Network (2004) NBN Gateway, National Biodiversity Network, UK, Available at http://www.searchnbn.net/index_homepage/index.jsp (verified 10 November 2009).

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