Helianthus tuberosus Risk – California Invasive Plant Council

Created by: Elizabeth D. Brusati
Created on: Wednesday, Jun 29th, 2016

Evaluation Summary

Summary:

General Evaluation Information

Date of Evaluation:

June 29, 2016

Evaluation Time (hrs):

Not Recorded

Evaluation Status:

Completed

Plant Information

Plant:

Helianthus tuberosus

Plant Material:

If the plant is a cultivar, and if the cultivar's behavior differs from its parent's (behavior), explain how:

Regional Information

Region Name:

California

Climate Matching Map

These maps were built using a toolkit created in collaboration between GreenInfo Network, PlantRight, Cal-IPC, and Agricultural Sustainability Institute at UC Davis.

Link to Climate Matching Map:

Climate Matching Maps PDF:

Invasive History and Climate Matching

1. Has the species (or cultivar or variety, if applicable; applies to subsequent "species" questions) become naturalized where it is not native?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Naturalized in the Azores, much of Europe, parts of Asia, Australia, New Zealand, Argentina, Uruguay. (Native to eastern and central United States.)

Reference(s):

USDA, ARS (2016). Germplasm Resources Information Network (GRIN).

2. Is the species (or cultivar or variety) noted as being naturalized in the US or world in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Of the areas listed by USDA GRIN, the following match California: Italy, France, Spain, Croatia, the Azores. The Jepson Manual does not list it as naturalized in California (it doesn't list this species at all) and there are only two points in Calflora, from 1969 and 1995, so it does not appear to be naturalized here. This species was placed on the Cal-IPC watchlist based on our article (Brusati et al 2014) finding it to be invasive in other Mediterranean regions and naturalized in California but the naturalization may have been an exaggeration.

Reference(s):

USDA, ARS (2016). Germplasm Resources Information Network (GRIN).

-IPC, C. (2016). Cal-IPC global map of climate areas matching California.

Jepson Flora Project (2014). Jepson eFlora.

Brusati, E. D., Johnson D. W., & DiTomaso J. (2014). Predicting invasive plants in California. California Agriculture. 68,

3. Is the species (or cultivar or variety) noted as being invasive in the U.S. or world?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Invasive in Romania. Included in study on the phenotype plasticity and functional traits in invasive plants there. One of the five most widespread species invading river floodplains in Central Europe. Listed as a major invader in Mediterranean France, defined as being widespread and having a significant ecological impact.

Reference(s):

Ruprecht, E., Fenesi A., & Nijs I. (2014). Are plasticity in functional traits and constancy in performance traits linked with invasiveness? An experimental test comparing invasive and naturalized plant species. Biological Invasions. 16, 1359–1372.

Podroužková, Š., Janovský Z., Horáčková J., & Juřičková L. (2015). Do snails eat exotic plant species invading river floodplains?. Journal of Molluscan Studies. 81, 139–146.

Brunel, S., & Tison J-M. (2005). A method of selection and hierarchisation and the invasive and potentially invasive plants in continental Mediterranean France..

4. Is the species (or cultivar or variety) noted as being invasive in the US or world in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

High

Answer / Justification:

Listed as a major invader in Mediterranean France, defined as being widespread and having a significant ecological impact.

Reference(s):

Brunel, S., & Tison J-M. (2005). A method of selection and hierarchisation and the invasive and potentially invasive plants in continental Mediterranean France..

5. Are other species of the same genus (or closely related genera) invasive in a similar climate?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

Several other species of Helianthus are listed in Randall 2012 but most are only indicated as naturalized. Several species are listed on the DAISIE invasives website for Europe but without much information. Helianthus ciliaris is listed by Randall as invasive in several areas, including California, where it is an A-rated noxious weed due to impacts in agricultural fields.

Reference(s):

Randall, R. (2012). A Global Compendium of Weeds. 2nd Edition..

[Anonymous] (0). DAISIE (Delivering Alien Invasive Species Inventories for Europe).

DiTomaso, J. M., & Healy E. A. (2007). Weeds of California and Other Western States. 1760.

6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

This is a widespread species that grows in much of North America and Europe, as well as scattered locations in other parts of the world.

Reference(s):

GBIF (0). Global Biodiversity Information Facility (GBIF).

-IPC, C. (2016). Cal-IPC global map of climate areas matching California.

Impact on Native Plants and Animals

7. Does this plant displace native plants and dominate (overtop or smother) the plant community in areas where it has established?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

Listed as a major invader in Mediterranean France, defined as being widespread and having a significant ecological impact based on field observations. The reference did not give details (it's just a list of species) but I am making the assumption than if it's considered a major invader, it must be displacing native plants.

Reference(s):

Brunel, S., & Tison J-M. (2005). A method of selection and hierarchisation and the invasive and potentially invasive plants in continental Mediterranean France..

8. Is the plant noted as promoting fire and/or changing fire regimes?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

No mention of this.

Reference(s):

9. Is the plant a health risk to humans or animals/fish? Has the species been noted as impacting grazing systems?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

Grown as a food crop and was eaten by Native Americans. The tubers are edible. Sold as sunchokes (this species is not actually related to artichokes, despite the name). Also eaten by snails in the Czech Republic. It was introduced into Europe partly as a food for pigs.

Reference(s):

Brenzel, K.. (2007). Sunset Western Garden Book.

Podroužková, Š., Janovský Z., Horáčková J., & Juřičková L. (2015). Do snails eat exotic plant species invading river floodplains?. Journal of Molluscan Studies. 81, 139–146.

[Anonymous] (0). Flora of North America. (Barkworth, M.., Ed.).

10. Does the plant produce impenetrable thickets, blocking or slowing movement of animals, livestock, or humans?

Yes or No:

Points:

Confidence Level:

Answer / Justification:

This is a sunflower that grows 10 ft tall. However, I don't have information on dense infestations or imprenetrable thickets.

Reference(s):

Reproductive Strategies

11. Does this species (or cultivar or variety) reproduce and spread vegetatively?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Reproduces from tubers.

Reference(s):

Brenzel, K.. (2007). Sunset Western Garden Book.

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

12. If naturally detached fragments from this plant are capable of producing new plants, is this a common method of reproduction for the plant?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

This does not seem likely given its biology.

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

13. Does the species (or cultivar or variety) commonly produce viable seed?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

Yes, produces many seeds.

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

14. Does this plant produce copious viable seeds each year (> 1000)?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

Could not find specific numbers but based on it being a form a sunflower I would assume yes. "Results showed that the seed fertilities of five collected varieties ranged from 2.4 % to 14.7 % and the number of seed produced by one plant ranged from 88 to 1058." http://agris.fao.org/agris-search/search.do?recordID=KR9036226

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

15. Is there significant germination (>25%) of seeds the next growing season, with no requirement of an infrequent environmental condition for seeds to germinate (i.e. fire) or long dormancy period?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

I would guess yes but couldn't find specific information. "Results showed that the seed fertilities of five collected varieties ranged from 2.4 % to 14.7 % and the number of seed produced by one plant ranged from 88 to 1058." http://agris.fao.org/agris-search/search.do?recordID=KR9036226

Reference(s):

16. Does this plant produce viable seed within the first three years (for an herbaceous species) to five years (for a woody species) after germination?

Yes or No:

Yes

Points:

Confidence Level:

Medium

Answer / Justification:

It's a large, fast-growing, perennial herb, i.e. a sunflower. I am guessing yes.

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

17. Does this plant continuously produce seed for >3 months each year or does seed production occur more than once a year?

Yes or No:

Points:

Confidence Level:

Very High

Answer / Justification:

In Britain, it flowers in October and seeds ripen in November. In its native range in North America, it flowers in August to October.

Reference(s):

Plants for a Future (2012). Plants for a Future (PFAF).

[Anonymous] (0). Flora of North America. (Barkworth, M.., Ed.).

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

Dispersal

18. Are the plant’s propagules frequently dispersed long distance (>100 m) by mammals or birds or via domestic animals?

Yes or No:

Yes

Points:

Confidence Level:

Very High

Answer / Justification:

The seeds are attractive to birds.

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

Birds seem to be the main form of seed dispersal.

Reference(s):

Lady Bird Johnson Wildflower Center (2016). Lady Bird Johnson Wildflower Center.

20. Are the plant’s propagules frequently dispersed via contaminated seed (agriculture or wildflower packets), equipment, vehicles, boats or clothing/shoes?

Yes or No:

Points:

Confidence Level:

High

Answer / Justification:

As it's a native sunflower in North America, it could be included in wildflower packets but I do not have information on this and it has not really naturalized in California. In other places, it seems to have spread from plantings.

Reference(s):

Evaluation Notes

USDA GRIN: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id=27946

Calflora: http://www.calflora.org/cgi-bin/county_taxon.cgi?where-calrecnum=8486

USDA PLANTS: http://plants.usda.gov/core/profile?symbol=HETU

GBIF: http://www.gbif.org/species/3119175

Flora of North America: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200024006

The Wildflower Center: http://www.wildflower.org/plants/result.php?id_plant=HETU

Total PRE Score