Hypericum grandifolium_Eric Wrubel_NPS
Photo courtesy Eric Wrubel, NPS

Hypericum grandifolium Risk Assessment

Common names: large-leaved hypericum

Hypericum grandifolium -- California

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Evaluation Summary
Summary: 
General Evaluation Information
Date of Evaluation: 
July 1, 2016
Evaluation Time (hrs): 
Not Recorded
Evaluation Status: 
Completed
Plant Information
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: 
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.
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: 
1
Confidence Level: 
Medium
Answer / Justification: 
USDA does not have any information on naturalization. Several locations have been recorded in Marin County, starting in 2010, but it is not listed by the Jepson Manual. GBIF shows a few locations in Spain and southeastern Australia. Naturalized in southeastern Australia at Mt. Napier and other sites near Hamilton, at Mt. Schanck, and at Telford Scrub Conservation Park (Atlas of Living Australia http://biocache.ala.org.au/occurrences/search?q=lsid%3Ahttp%3A%2F%2Fid.b...)
Reference(s): 
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: 
2
Confidence Level: 
Medium
Answer / Justification: 
USDA does not have any information on naturalization. Several locations have been recorded in Marin County, starting in 2010, but it is not listed by the Jepson Manual. GBIF shows a few locations in continental Spain and southeastern Australia. (I found one reference from Spain but it was from the native range in the Canary Islands.)
3. Is the species (or cultivar or variety) noted as being invasive in the U.S. or world?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
Medium
Answer / Justification: 
Global compendium of weeds (Randall 2012): environmental weed Environmental Weed List Victoria. Supplied by Weedmanager.Net (Source not cited but possibly drawn from Carr et al. Environmental Weeds of Victoria) (environmental weed) Groves, R.H. & Hosking, J.R. (1997) Recent Incursions of Weeds to Australia. Technical Series N° 3. CRC for Weed Management Systems, Australia. (weed) John Hosking, NSW Department of Agriculture, Weed Database 30 April 2003 (environmental weed, naturalised) 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. (weed) The Exotic Flora of Victoria. (1998) Data supplied by Department of Natural Resources and Environment, Victoria, State Herbarium. (naturalised) Flora of Victoria https://vicflora.rbg.vic.gov.au/flora/taxon/78b6e8ae-6809-4cb8-8e57-eadb20733e9e Apparently confined to the Hamilton district where a weed of roadsides, rail-lines and bushland (e.g. at Mt Napier).
Reference(s): 
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: 
3
Confidence Level: 
Medium
Answer / Justification: 
Environmental weed in southeastern Australia, which overlaps with the climate of California in parts (Cal-IPC).
Reference(s): 
5. Are other species of the same genus (or closely related genera) invasive in a similar climate?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Very High
Answer / Justification: 
Several species of Hypericum are invasive plants in California and elsewhere. H. canariense and H. perforatum are both rated Moderate on the Cal-IPC Inventory because they have formed dense infestations and displaced native species. H. perforatum covered 2 million acres in California before it was reduced by a biocontrol insect.
Reference(s): 
6. Is the species (or cultivar or variety) found predominately in a climate matching the region of concern?
Yes or No: 
Yes
Points: 
2
Confidence Level: 
High
Answer / Justification: 
Native to Madeira and the Canary Islands. Possible naturalization in Spain and southeastern Australia. All of these areas are similar to 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: 
1
Confidence Level: 
Medium
Answer / Justification: 
Based on personal observations from Eric Wrubel. Formed dense stands at two locations in Marin County. It is unclear if these populations were introduced by planting or dumped garden waste, but they spread vegetatively into natural coastal scrub and riparian vegetation, displacing native plants.
Reference(s): 
8. Is the plant noted as promoting fire and/or changing fire regimes?
Yes or No: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
No information so this answer defaults to no.
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: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
In the Canary Islands, this and other Hypericum species are traditionally used as diuretic, wound healing, vermifuge, sedative and antidepressive agents.
Reference(s): 
10. Does the plant produce impenetrable thickets, blocking or slowing movement of animals, livestock, or humans?
Yes or No: 
No
Points: 
0
Confidence Level: 
Medium
Answer / Justification: 
H. grandifolium is an evergreen shrub up to 1.8 m in height (GBIF) but lacks spines or thorns and is not known to form impenetrable thickets.
Reproductive Strategies
11. Does this species (or cultivar or variety) reproduce and spread vegetatively?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Based on personal observation from Eric Wrubel: This is a rhizomatous species. Forms thickets, which appear to arise from rootstock. In 2011 BAEDN contractors removed a large patch of numerous H. grandifolium shrubs growing in coastal scrub below Hwy 1 at Green Gulch. In 2014 mature plants had grown back from remaining root fragments, indicating that the species is rhizomatous.
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: 
Yes
Points: 
1
Confidence Level: 
Medium
Answer / Justification: 
Based on personal observation from Eric Wrubel: This is a rhizomatous species. Forms thickets, which appear to arise from rootstock. In 2011 BAEDN contractors removed a large patch of numerous H. grandifolium shrubs growing in coastal scrub below Hwy 1 at Green Gulch. In 2014 mature plants had grown back from remaining root fragments, indicating that the species is rhizomatous.
13. Does the species (or cultivar or variety) commonly produce viable seed?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
High
Answer / Justification: 
Other Hypericum species reproduce from seed so H. grandifolium likely does too.
Reference(s): 
14. Does this plant produce copious viable seeds each year (> 1000)?
Yes or No: 
Points: 
Confidence Level: 
Answer / Justification: 
No information is available on the number of seeds produced by each H. grandifolium plant.
Reference(s): 
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: 
Points: 
Confidence Level: 
Answer / Justification: 
No information is available on the percentage of seed germination or dormancy of H. grandifolium.
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: 
Points: 
Confidence Level: 
Answer / Justification: 
No information is available on the amount of time needed for H. grandifolium to reach reproductive maturity
Reference(s): 
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: 
Answer / Justification: 
Flowers from April to July in Spain.
Reference(s): 
Dispersal
18. Are the plant’s propagules frequently dispersed long distance (>100 m) by mammals or birds or via domestic animals?
Yes or No: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
There is no documentation of H. grandifolium dispersal by birds or mammals.
Reference(s): 
19. Are the plant’s propagules frequently dispersed long distance (>100 m) by wind or water?
Yes or No: 
Yes
Points: 
1
Confidence Level: 
Low
Answer / Justification: 
This species is present on all of the Canary Islands, and seeds were found to be 100% bouyant and viable when floated in salt water for one week. Vazacˇova´ K, Mu¨nzbergova´ Z (2014) The Importance of Species Traits for Species Distribution on Oceanic Islands. PLoS ONE 9(7): e101046. doi:10.1371/journal.pone.0101046
Reference(s): 
20. Are the plant’s propagules frequently dispersed via contaminated seed (agriculture or wildflower packets), equipment, vehicles, boats or clothing/shoes?
Yes or No: 
No
Points: 
0
Confidence Level: 
Low
Answer / Justification: 
There is no documentation of H. grandifolium dispersal by contaminated seed, equipment, vehicles or clothing.
Reference(s): 
Evaluation Notes

Insufficient information to complete an evaluation. I do not want to extrapolate information from other Hypericum species without evidence. A journal literature search found no relevant information. Not much online. Although this is suspected to have spread from horticultural plantings in Marin County, the species is not listed in the Sunset Western Garden Book, Dave's Garden website, or Royal Horticultural Society website. The identification of the Marin plants was confirmed by the CA Dept of Food and Agriculture herbarium.

Note from reviewer Chris McDonald, UC Cooperative Extension (UC Riverside): I agree there isn't much info on this species to finish the evaluation. However, based on the few sites in Marin Co. it appears to be spreading to new sites, unless it was purposfully seeded or transported.

USDA: https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id=19570

GBIF: http://www.gbif.org/species/3712155

Calflora: http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=11142

Spain (Canary Islands): http://www.magrama.gob.es/es/red-parques-nacionales/nuestros-parques/gar...

Reviewed by Chris McDonald and Eric Wrubel.

Total PRE Score

  • < 13 : accept (low risk of invasiveness)
  • 13 - 15 : evaluate further
  • > 15 : reject (high risk of invasiveness)

PRE Score: 
16
Number of questions answered: 
16
Screener Confidence (%): 
62.5
PRE Content Access and Privacy
Evaluation visibility: 
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