Curlycup gumweed (Grindelia squarrosa)

Present distribution

Scientific name:	Grindelia squarrosa (Pursh) Dunal
Common name(s):	curlycup gumweed, pitch weed

Map showing the present distribution of this weed.

Habitat:

Typically found at an altitude of 0 to 3,180 meters (ZipcoceZoo 2009). Occurs on saltflats and in wet lowlands (USDA 2010). A species typical of montane woodland, such as Grindelia squarrosa (Bennett et al. 1996). A weed of pastures, fields and roadsides (Steyermark 1934); predominantly a species of open places, and is practically absent from wooded areas and forests (Steyermark 1937). G. squarrosa among plants observed in temporarily and seasonally flooded depressional wetlands and intermittent and ephemeral riverine wetlands (Jones 2004). Gumweed does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops (Saskatchewan 2007). Dry prairies, waste places, railroads, depleted rangelands, and abandoned croplands (Utah Uni 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; pasture dryland; pasture irrigation

Ecological Vegetation Divisions
Coastal; grassy/heathy dry forest; rocky outcrop shrubland; semiarid woodland; saline wetland; chenopod shrubland

Colours indicate possibility of Grindelia squarrosa 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 grindelia squarrosa

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

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Curlycup gumweed is a biennial or short-lived perennial that can form dense, brushlike cover in rangelands. The coats of livestock can become gummed with a sticky exudate produced by stems, leaves, and flowers (Walsh 1993). This plant often forms almost pure stands (Utah Uni 2002). In dense infestations, livestock are reluctant to graze between plants (Saskatchewan 2007). Although G. squarrosa favours dry areas (Utah Uni 2002), it is known to also occur along streams (eFNA 2010) and intermittent and ephemeral riverine wetlands (Jones 2004). Major impediment to access waterways. Significant works required to provide reasonable access.	H	MH
2. Reduce tourism?	Curlycup gumweed can form dense, brushlike cover in rangelands. Stems, leaves, and flowers produce a sticky exudate. The coats of livestock can become gummed with it (Walsh 1993). The bracts at the base of the flowers are sticky, and the leaves gummy. This plant often forms almost pure stands (Utah Uni 2002). Although G. squarrosa favours dry areas (Utah Uni 2002), it is known to also occur along streams (eFNA 2010) and intermittent and ephemeral riverine wetlands (Jones 2004). Major impact on recreation. Weeds obvious to most visitors.	H	MH
3. Injurious to people?	Can have toxic properties, especially when excessive selenium is absorbed the plant becomes poisonous (Saskatchewan 2007). Flowers are numerous; floral bracts at the base of the flower are shiny, sticky, and curved downward; leaves are alternate and oblong with toothed edges, gland-dotted, and gummy (Utah Uni 2002). Coats of livestock can become gummed with a sticky exudate produced by stems, leaves, and flowers (Walsh 1993). Mildly toxic, may cause some physiological issues.	ML	MH
4. Damage to cultural sites?	Curlycup gumweed is a perennial or biennial plant; grows 0.1–1 m, with one to several branched; is taprooted, and develops a short, vertical rhizome. The root system extends 2 m into the soil, with extensive shallow root development. Stems, leaves, and flowers produce a sticky exudate (Walsh 1993). This plant often forms almost pure stands (Utah Uni 2002). Major structural damage to site and/or obliteration of the heritage/cultural feature.	H	H
Abiotic
5. Impact flow?	This plant often forms almost pure stands (Utah Uni 2002). Curlycup gumweed is a perennial or biennial that grows 0.1–1 m, with one to several branched; is taprooted, and develops a short, vertical rhizome. The root system extends 2 m into the soil, with extensive shallow root development. Stems, leaves, and flowers produce a sticky exudate (Walsh 1993). Although G. squarrosa favours dry areas (Utah Uni 2002), it is known to also occur along streams (eFNA 2010). and intermittent and ephemeral riverine wetlands (Jones 2004). Major impact on either surface or subsurface flow.	MH	MH
6. Impact water quality?	This plant often forms almost pure stands (Utah Uni 2002). Stems, leaves, and flowers produce a sticky exudate (Walsh 1993). Although G. squarrosa favours dry areas (Utah Uni 2002), it is known to also occur along streams (eFNA 2010). and intermittent and ephemeral riverine wetlands (Jones 2004). Noticeable but minor effects in either dissolved O₂ or light levels.	ML	MH
7. Increase soil erosion?	Curlycup gumweed is taprooted, and develops a short, vertical rhizome. The root system extends 2 m into the soil, with extensive shallow root development (Walsh 1993). Coarse biennial or weak perennial from 30–90 cm; root systems with underground rhizome system can reach depths of two metres (Saskatchewan 2007). Low probability of large scale soil movement; decreases the probability of soil erosion.	L	H
8. Reduce biomass?	This plant often forms almost pure stands (Utah Uni 2002). Curlycup gumweed is a perennial or biennial plant that 0.1–1 m, with one to several branched (Walsh 1993). Occurs in dry prairies, waste places, roadsides, railroads, depleted rangelands, and abandoned croplands (Utah Uni 2002). Biomass may increase.	L	MH
9. Change fire regime?	Curlycup gumweed colonizes disturbed [burnt] areas, and establishes or increases after fire (Walsh 1993). This plant often forms almost pure stands (Utah Uni 2002). Plant populations increase under drought conditions (Saskatchewan 2007). Minor change to either frequency or intensity of fire.	ML	ML
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Semi-arid Chenopod Shrubland (V); CMA = Mallee; Bioregion = Murray Mallee; VH CLIMATE potential. Serious changes in the structure of semi-natural steppe communities are caused by Grindelia squarrosa (Protopopova and Shevera 1999). An erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems; often forms almost pure stands (Utah Uni 2002). Major displacement of some dominant species within a strata/layer (or some dominant species within different layers).	MH	MH
(b) medium value EVC	EVC = Grassy Dry Forest (D); CMA = Wimmera; Bioregion =Goldfields; VH CLIMATE potential. Serious changes in the structure of semi-natural steppe communities are caused by Grindelia squarrosa (Protopopova and Shevera 1999). An erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems; often forms almost pure stands (Utah Uni 2002). Major displacement of some dominant species within a strata/layer (or some dominant species within different layers).	MH	MH
(c) low value EVC	EVC = Shrubby Dry Forest (LC); CMA = North East; Bioregion = Northern Inland Slopes; VH CLIMATE potential. Serious changes in the structure of semi-natural steppe communities are caused by Grindelia squarrosa (Protopopova and Shevera 1999). An erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems; often forms almost pure stands (Utah Uni 2002). Major displacement of some dominant species within a strata/layer (or some dominant species within different layers).	MH	MH
11. Impact on structure?	Serious changes in the structure of semi-natural steppe communities are caused by Grindelia squarrosa (Protopopova and Shevera 1999). An erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems; often forms almost pure stands (Utah Uni 2002). Minor effect on >60% of the layers or major effect on <60% of the floral strata.	MH	MH
12. Effect on threatened flora?	Serious changes in the structure of semi-natural steppe communities are caused by Grindelia squarrosa (Protopopova and Shevera 1999). An erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems; often forms almost pure stands (Utah Uni 2002). Any population of Bioregional Priority 1A spp. is reduced, or any population of VROT spp. is replaced.	MH	L
Fauna
13. Effect on threatened fauna?	If curlycup gumweed is consumed, it may lead to poisoning due to the selenium the plant can accumulate (Utah Uni 2002). Plants growing on high-selenium soils can accumulate selenium, sometimes to levels that are toxic to livestock (DiTomaso 2007). Curlycup gumweed is not palatable to livestock or big game (Saskatchewan 2007). Minor effects on threatened fauna species.	ML	MH
14. Effect on non-threatened fauna?	If curlycup gumweed is consumed, it may lead to poisoning due to the selenium the plant can accumulate (Utah Uni 2002). Plants growing on high-selenium soils can accumulate selenium, sometimes to levels that are toxic to livestock (DiTomaso 2007). Curlycup gumweed is not palatable to livestock or big game (Saskatchewan 2007). Minor effects on non-threatened fauna species.	ML	MH
15. Benefits fauna?	Curlycup gumweed is a perennial or biennial plant; grows 0.1–1 m, with one to several branched; provides a fair level of cover for a number of wildlife species (Walsh 1993). This plant often forms almost pure stands (Utah Uni 2002). Curlycup gumweed is not palatable to livestock (Walsh 1993) or big game (Saskatchewan 2007). Provides shelter for desirable species.	L	MH
16. Injurious to fauna?	If curlycup gumweed is consumed, it may lead to poisoning due to the selenium the plant can accumulate (Utah Uni 2002). Plants growing on high-selenium soils can accumulate selenium, sometimes to levels that are toxic to livestock (DiTomaso 2007). However, curlycup gumweed is not palatable to livestock (Walsh 1993) or big game (Saskatchewan 2007). Mildly toxic; may cause fauna to lose condition.	ML	MH
Pest Animal
17. Food source to pests?	G. squarrosa was among the commonly identified food sources for sage-grouse birds in USA (BHSBLWG 2007). Curlycup gumweed is not palatable to livestock (Walsh 1993) or big game (Saskatchewan 2007). Provides minimal food for pest animals.	L	MH
18. Provides harbour?	Curlycup gumweed is a perennial or biennial plant; grows 0.1–1 m, with one to several branched; provides a fair level of cover for a number of wildlife species (Walsh 1993). This plant often forms almost pure stands (Utah Uni 2002). Curlycup gumweed is not palatable to livestock or big game (Saskatchewan 2007). Capacity to harbour permanent warrens for foxes and rabbits throughout the year.	H	MH
Agriculture
19. Impact yield?	Curlycup gumweed increases with grazing, and has a negative economic impact on rangelands where it forms a dense brushlike cover (Walsh 1993). In dense infestations, livestock are reluctant to graze between plants, leaving some grasses ungrazed. Does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops (Saskatchewan 2007). This plant often forms almost pure stands (Utah Uni 2002). Major impact on quantity of produce, e.g. 5–20%.	MH	H
20. Impact quality?	The coats of livestock can become gummed with a sticky exudate produced by stems, leaves, and flowers (Walsh 1993). Does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops (Saskatchewan 2007). Minor impact on quality of produce, e.g. <5% reduction.	ML	MH
21. Affect land value?	Curlycup gumweed increases with grazing, and has a negative economic impact on rangelands where it forms a dense brushlike cover (Walsh 1993). In dense infestations, livestock are reluctant to graze between plants, leaving some grasses ungrazed. Does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops; no herbicides give consistent results (Saskatchewan 2007). Major significance >10%.	H	H
22. Change land use?	Curlycup gumweed increases with grazing, and has a negative economic impact on rangelands where it forms a dense brushlike cover. The coats of livestock can become gummed the sticky exudate from plants (Walsh 1993). In dense infestations, livestock are reluctant to graze between plants, leaving some grasses ungrazed. Does not tolerate frequent disturbance, and is therefore rarely a problem in annual crops; no herbicides give consistent results (Saskatchewan 2007). Downgrading of the priority landuse.	MH	MH
23. Increase harvest costs?	The coats of livestock can become gummed with a sticky exudate produced by stems, leaves, and flowers (Walsh 1993). Minor increase in cost of harvesting, e.g. slightly more time or labour is required.	M	H
24. Disease host/vector?	Adults of the root-boring weevil Heilipodus ventralis fed mostly on 6 species of the closely related genera Grindelia, Gutierrezia, and Gymnosperma (DeLoach and Cuda 1999). Provides host to minor (or common) pests or diseases.	M	H

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Curlycup gumweed seeds were stratified for 10 weeks with a cold, damp regime. When planted, germination time was 3 days (Walsh 1993). Seeds exhibit physiological dormancy. Pre-Planting Treatments: seeds are placed in cold moist stratification for 60 to 90 days; germination occurs at 22º C, 25D/20N C alternating temperature cycle; germination was greater in light than dark (Baskin and Baskin 2002). Requires natural seasonal disturbances.	MH	H
2. Establishment requirements?	Curlycup gumweed favours dry areas, but grows on moist soils that lack other vegetation. Does best on sandy loam, loam, and clayey loam, although it is adapted to a broad range of soils. It is most common in dry prairies, waste places, roadsides, railroads, depleted rangelands, and abandoned croplands (Utah Uni 2002). A weed of pastures and fields (Steyermark 1934); predominantly a species of open places, and is practically absent from wooded areas and forests (Steyermark 1937). Requires specific requirements to establish, e.g. open space or bare ground.	ML	MH
3. How much disturbance is required?	Curlycup gumweed colonises disturbed sites (Walsh 1993). Occurs on disturbed sites, plains, hills, roadsides (ZipcodeZoo 2009). Common in dry prairies, waste places, roadsides, railroads, depleted rangelands, and abandoned croplands (Utah Uni 2002). Establishes in highly disturbed natural ecosystems or in overgrazed pastures/poorly growing or patchy crops.	ML	MH
Growth/Competitive
4. Life form?	Annual, biennial, or perennial; erect, tall forb, growing 1 to 3 feet tall, with 1 to several branched stems. Grows from a taproot, branching above (Utah Uni 2002). Curlycup gumweed is a warm-season perennial or biennial native forb; grows 0.1–1 m, with one to several branched; is taprooted, and develops a short, vertical rhizome. The root system extends 2 m into the soil, with extensive shallow root development (Walsh 1993). Annuals, biennials, perennials, or subshrubs (10–) 40–100 cm (eFNA 2010). Geophyte.	ML	MH
5. Allelopathic properties?	Allelopathic properties of Grindelia squarrosa have not yet been determined.	M	L
6. Tolerates herb pressure?	If curlycup gumweed is consumed, it may lead to poisoning due to the selenium the plant can accumulate. It is resistant to grazing (Utah Uni 2002). Curlycup gumweed is unpalatable to big game (Saskatchewan 2007), cattle, sheep, and horses, though sheep will occasionally crop flower heads in the absence of other forage. Tannins, volatile oils, resins, bitter alkaloids, and glucosides give curlycup gumweed an unpleasant taste (Walsh 1993). Favoured by heavy grazing pressure as not eaten by animals.	H	MH
7. Normal growth rate?	In North Dakota, curlycup gumweed began growth in May, and by the end of May had attained 50 percent of its yearly growth. Curlycup gumweed attained maximum height in August. The average length of flowering period was 41 days; the median date when flowering was 95 percent complete was September 4 (Walsh 1993). Starts growth in early spring, flowers July to August (Utah Uni 2002). Moderately rapid growth that will equal competitive species of the same life form.	MH	MH
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Curlycup gumweed increases under drought conditions, and is tolerant of saline soils (Utah Uni 2002). Curlycup gumweed is highly drought resistant due to deep roots and resinous secretions, and may be abundant after dry periods; maybe top-killed by fire, but may sprout from its short, vertical rhizome after fire (Walsh 1993). Tolerant to at least two and susceptible to at least one.	ML	MH
Reproduction
9. Reproductive system	Reproduces from seeds (Whitson et al. 1992; Utah Uni 2002; DiTomaso 2007). Curlycup gumweed seeds probably establishes on burned sites by wind-dispersed seed (Walsh 1993). Sexual (either cross or self-pollination.	L	MH
10. Number of propagules produced?	The plant has strongly divergent, many-flowered branchlets; flower heads numerous (Steyermark 1934). Calculated on the basis of published plant descriptions, e.g. Steyermark (1934) and Walsh (1993), and available photographs, e.g. Whitson et al. (1992), the number of propagules per flowering event would exceed 2000.	H	ML
11. Propagule longevity?	Deeply buried seeds can survive up to 5 years (DiTomaso 2007). Seeds of Grindelia squarrosa exhibit physiological dormancy (Baskin and Baskin 2002). Greater than 25% of seeds survive for 5 years.	L	H
12. Reproductive period?	Curlycup gumweed is a warm-season perennial or biennial native forb; the average length of flowering period was 41 days. Attractive as an ornamental because it produces flowers over a long period, even when the soil is poor and dry (Walsh 1993). G. squarrosa plants are biennials, perennials, or subshrubs (eFNA 2010). Mature plants produce viable propagules for 3–10 years.	MH	MH
13. Time to reproductive maturity?	Starts growth in early spring, flowers July to August (Utah Uni 2002). In North Dakota, curlycup gumweed began growth in May; the median date when flowering was 95 percent complete was September 4 (Walsh 1993). Reaches maturity and produces viable propagules in under a year.	H	MH
Dispersal
14. Number of mechanisms?	Curlycup gumweed reproduces from seeds (Utah Uni 2002) which have a pappus, and are dispersed by wind (Walsh 1993; eFNA 2010). Although G. squarrosa favours dry areas (Utah Uni 2002), it is known to also occur along streams (eFNA 2010) and intermittent and ephemeral riverine wetlands (Jones 2004). Seeds are wind dispersed or dispersal by water or highly mobile animals.	H	MH
15. How far do they disperse?	Curlycup gumweed seeds have a pappus, and are dispersed by wind. Also, the coats of livestock can become gummed with a sticky exudate produced by stems, leaves, and flowers (Walsh 1993). G. squarrosa is known to occur along streams (eFNA 2010) and intermittent and ephemeral riverine wetlands (Jones 2004). Very likely that at least one propagule will disperse greater than one kilometre.	H	MH

References

Baskin CC and Baskin JM. (2002) Propagation protocol for production of container Grindelia squarrosa (Pursh) Dun. plants; University of Kentucky, Lexington, Kentucky. In: Native Plant Network. Moscow (ID): University of Idaho, College of Natural Resources, Forest Research Nursery. Available at http://www.nativeplantnetwork.org/network/ViewProtocols.aspx?ProtocolID=1837 (verified 12 May 2010).

BHSBLWG (2007) Bates Hole/Shirley Basin Sage-grouse Conservation Plan. The Bates Hole/Shirley Basin Sage-grouse Working Group. Available at
http://gf.state.wy.us/wildlife/wildlife_management/sagegrouse/BatesHoleShirleyBasin/BHSBLWG%20Final%20Conservation%20Plan.pdf (verified 13 May 2010).

Bennett B, Dewey E, Korb J and Meloche C. (1996) Vegetation of the Gregory-Long Canyon Watershed. Available at
http://ci.boulder.co.us/files/openspace/pdf_gis/IndependentResearchReports/4080_Bennett_Barry_Vegetation.pdf (verified 10 May 2010).

DeLoach CJ and Cuda JP. (1999) Host Specificity of the Argentine Root-Boring Weevil, Heilipodus ventralis (Coleoptera: Curculionidae), a Potential Biocontrol Agent for Snakeweeds (Gutierrezia: Asteraceae) in Western North American Rangelands—U.S. Quarantine Tests. Biological Control 15(3): 185–209. Available at http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBP45GW8B41M&_user=141304&_coverDate=07%2F31%2F1999&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1333538418&_rerunOrigin=scholar.google&_acct=C000011678&_version=1&_urlVersion=0&_userid=141304&md5=75a89338cb5f4d6dc26208a5ec8fa60f (verified 13 May 2010).

DiTomaso JM. (2007) Weeds of California and Other Western States. Grindelia squarrosa. Vol. 1. pp. 325–328. University of California, Agriculture and Natural Resources, Publication No. 3488. Available at
http://books.google.com.au/books?hl=en&lr=&id=qygJW0HC1AkC&oi=fnd&pg=PT13&dq=%22Curlycup+gumweed%22+frost&ots=gQxP_7GjEx&sig=d0h_c2Ya-Dh0R_ri5cR5imFGllo#v=onepage&q=squarrosa&f=false (verified 13 May 2010).

eFNA (2010) Flora of North America, Vol. 20 Grindelia squarrosa (Pursh) Dunal. Available at http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242416609 (verified 7 May 2010).

Jones WM. (2004) Using vegetation to assess wetland condition. Montana Natural Heritage Program. Available at http://mtnhp.org/plants/reports/DEQ_Wetland_Assess.pdf (verified 12 May 2010).

Protopopova V and Shevera M. (1999) Analysis if the modern phytoinvasions in Ukraine. In Proceedings 5th International Conference on the Ecology of Invasive Alien Plants, 13- 16 October 1999 - La Maddalena - Sardinia – Italy 5th ICEIAP - pp. 96–97. Available at
http://www.hear.org/iceiap/1999/1999_iceiap_proceedings.pdf (verified 7 May 2010).

Saskatchewan (2007) Government of Saskatchewan, Department of Agriculture, Problem Weeds: A Cattleman’s Guide, Grindelia squarrosa. Available at
http://www.agriculture.gov.sk.ca/Problem_Weeds_Cattlemens_Guide (verified 24 May 2010).

Steyermark JA. (1934) Studies in Grindelia. II. A Monograph of the North American Species of the Genus Grindelia. Annals of the Missouri Botanical Garden, 21(3): 433–608. Available at http://www.jstor.org/pss/2394201 (verified 12 May 2010).

Steyermark JA. (1937) Studies in Grindelia. III. Annals of the Missouri Botanical Garden 24(2): 225–262. Available at http://www.jstor.org/pss/2394206 (verified 10 May 2010).

Walsh RA. (1993) Grindelia squarrosa. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available at http://www.fs.fed.us/database/feis/plants/forb/grisqu/all.html (verified 10 May 2010).

Whitson TD, Burrill LC, Dewey SA, Cudney DW, Nelson BE, Richard DL and Parker R. (1992) Weeds of the West. Western Society of Weed Science, CA, USA.

Utah Uni (2002) Utah University, Range Plants of Utah. Available at http://extension.usu.edu/range/forbs/curlycupgumweed.htm (verified 7 May 2010).

ZipcodeZoo (2009) ZipcodeZoo, Grindelia squarrosa page. Available at http://zipcodezoo.com/Plants/G/Grindelia_squarrosa/ (verified 7 May 2010).

Global present distribution data references

Australian National Herbarium (ANH) (2010) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at
http://www.anbg.gov.au/avh/ (verified 12 May 2010).

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 10 May 2010).

Global Biodiversity Information Facility (GBIF) (2010) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 12 May 2010).

Integrated Taxonomic Information System. (2010) Available at http://www.itis.gov/ (verified 16 March 2010).

Royal Botanic Gardens Melbourne. (2003) Census of Vascular Plants of Victoria. Available at http://www.rbg.vic.gov.au/research_and_conservation/plant_information/viclist (verified 16 March 2010).

USDA (2010) United States Department of Agriculture. Natural Resources Conservation Service. Plants Profile Grindelia squarrosa. Available at
http://plants.usda.gov/java/profile?symbol=GRSQ (verified 16 March 2010).

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