Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Hypericum perforatum; common St. Johnswort

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

y

1.03

Does the species have weedy races?

y=-1, n=-1

n

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

1

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

2

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

y

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

y

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

n

4.05

Toxic to animals

y=1, n=0

y

4.06

Host for recognized pests and pathogens

y=1, n=0

n

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

4.1

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

y

6.04

Self-compatible or apomictic

y=1, n=-1

y

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

y

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

y

7.08

Propagules survive passage through the gut

y=1, n=-1

n

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

y

8.03

Well controlled by herbicides

y=-1, n=1

y

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

y

Total score:

12

Source

Notes

1.01

no evidence

1.02

Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.

AB: "Originally introduced for ornamental or medicinal purposes the sp. has now spread to many locations, occurring on hillsides, roadsides, river banks, railways and pasture lands."

1.03

Bourke, C. A.; Southwell, I. A.; Mayo, G. M. (2002) Sheep as biological control agents against St. John's wort (Hypericum perforatum L.): factors affecting hypericin variation and hypericin tolerance. NSW Agriculture, Orange Agricultural Institute, Forest Road, Orange, NSW 2800, Australia. pp.398-401, 6 ref.

AB: The seasonal variation in hypericin production by two biotypes of H. perforatum was determined on field grown plants. It varied from <100 ppm to almost 5000 ppm.

2.01

(1)USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?19600 (12 February 2003) (2)http://www.stevenfoster.com/education/monograph/hypericum.html

Native distribution:
Africa: Algeria [n.]; Morocco; Portugal - Azores, Madeira Islands; Spain - Canary Islands; Tunisia
Asia-Temperate: Afghanistan; Armenia; Azerbaijan; China - Gansu, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang; Cyprus; Georgia; Iran; Iraq; Kazakhstan; Kyrgyzstan; Lebanon; Mongolia; Russian Federation - Ciscaucasia, Dagestan, Western Siberia; Syria; Tajikistan; Turkey; Turkmenistan
Asia-Tropical: India [n.w.]; Pakistan
Europe: Albania; Austria; Belarus; Belgium; Bulgaria; Czechoslovakia; Denmark; Finland; France [incl. Corsica]; Germany; Greece [incl. Crete]; Hungary; Ireland; Italy [incl. Sardinia, Sicily]; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation - European part; Spain [incl. Baleares]; Sweden; Switzerland; Ukraine [incl. Krym]; United Kingdom; Yugoslavia
[temperate to subtropical]
Other: widely naturalized elsewhere (2)St. John's wort is native to Europe

2.02

2.03

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?19600 (12 February 2003)

[temperate to subtropical]

2.04

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?19600 (12 February 2003)

Native distribution:
Africa: Algeria [n.]; Morocco; Portugal - Azores, Madeira Islands; Spain - Canary Islands; Tunisia
Asia-Temperate: Afghanistan; Armenia; Azerbaijan; China - Gansu, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang; Cyprus; Georgia; Iran; Iraq; Kazakhstan; Kyrgyzstan; Lebanon; Mongolia; Russian Federation - Ciscaucasia, Dagestan, Western Siberia; Syria; Tajikistan; Turkey; Turkmenistan
Asia-Tropical: India [n.w.]; Pakistan
Europe: Albania; Austria; Belarus; Belgium; Bulgaria; Czechoslovakia; Denmark; Finland; France [incl. Corsica]; Germany; Greece [incl. Crete]; Hungary; Ireland; Italy [incl. Sardinia, Sicily]; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation - European part; Spain [incl. Baleares]; Sweden; Switzerland; Ukraine [incl. Krym]; United Kingdom; Yugoslavia
[temperate to subtropical]
Other: widely naturalized elsewhere (2)St. John's wort is native to Europe

2.05

(1) Syrett, P. (1997) Biological control of St. John's wort in New Zealand. Plant Protection Quarterly, 1997, Vol.12, No.2, pp.88-90, 15 ref.
(2) Harris, J. A.; Gill, A. M. (1997) History of the introduction and spread of St. John's wort (Hypericum perforatum L.) in Australia. Plant Protection Quarterly, 1997, Vol.12, No.2, pp.52-56, 39 ref.
(3) Mitich, L. W. (1994) Common St. Johnswort. Weed Technology, 1994, Vol.8, No.3, pp.658-661, 18 ref.

(1) New Zealand, (2) Australia, (3) USA

3.01

Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.

AB: "Originally introduced for ornamental or medicinal purposes the sp. has now spread to many locations, occurring on hillsides, roadsides, river banks, railways and pasture lands."

3.02

Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.

AB: "Originally introduced for ornamental or medicinal purposes the sp. has now spread to many locations, occurring on hillsides, roadsides, river banks, railways and pasture lands."; "There is no correlation between soil type and infestation, but some correlation between infestation and land use. "
[disturbance seems to promote invasion]

3.03

(1) Syrett, P. (1989) Hypericum perforatum L., St. John's wort (Clusiaceae). Technical Communication - CAB International Institute of Biological Control, 1989, No.10, pp.353-356, 15 ref.
(2) Pilegaard, K.; Ladefoged, O. (1999) Wild plants that can cause poisoning in farm animals. [FT: Vilde planter som kan forarsage forgiftning hos produktionsdyr.] Dansk Veterinaertidsskrift, 1999, Vol.82, No.15, pp.666-668, 14 ref.

(1) AB: "The weed contains hypericin which causes photosensitivity in sheep and cattle."
(2) AB: "Descriptions are given of 4 wild plants that have become more abundant in Denmark and have caused poisoning of farm animals in neighbouring countries. The plants are Eastern groundsel (Senecio vernalis ), black nightshade (Solanum nigrum ), bog asphodel (Narthecium ossifragum ) and common St John's wort (Hypericum perforatum )."

3.04

(1)Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref. (2)http://www.fs.fed.us/r9/weed/Sec3B.htm

(1) "Originally introduced for ornamental or medicinal purposes the sp. has now spread to many locations, occurring on hillsides, roadsides, river banks, railways and pasture lands. " (2)plants are often restricted to disturbed ground, and are not especially invasive in undisturbed natural habitats.

3.05

Bacon, P., P.J. Terry, N. Waltham, & P.Castro S. (1997) An Electronic Atlas of World Weed and Invasive Plants. Version 1.0, 1997. A database based on the original work "A Geographical Atlas of World Weeds" by Holm et al 1979.

H. androsaemum was reported as a principal weed in New Zealand; H. elodes was reported as a common weed in Portugal; H. ereetum, H. itxum were reported as a common weed in Japan; H. erispum was repoterd as a principal weed in Tinisia , and common weed in Lebanon; H. japonicum was reported as a common weed inTaiwan; H. maeulatum was reported as a common weed in Finland; H. perforatum was reported as a serious weed in Australia and United States; as a principal weed in Hungary, Italy, Sweden, and Turkey; as a common weed in Canada, Iran, Poland, South Africa and Russian Federation; H. quadrangulum was reported as a common weed in Russian Federation; H. triquetrifolium was reported as a common weed in Lebanon.

4.01

http://www.montana.edu/wwwpb/pubs/mt9810.pdf

no description of these traits

4.02

Mar'yushkina, V. Ya.; Kovalev, O. V. (1989) Allelopathic activity of species as representatives of the root stage of stratum succession. Trudy Zoologicheskii Institut, Akademii Nauk SSSR, 1989, Vol.189, pp.221-223, 16 ref.

AB: "Allelopathic activity was studied in 2 biennial (Daucus carota and Arctium tomentosum ) and 5 perennial weeds (Elymus repens, Achillea nobilis, Cirsium incanum, Hypericum perforatum and Cichorium intybus ) replacing Ambrosia artemisiifolia in natural plant successions. The biennial species generally had lower allelopathic activity than the perennial species, and tended to produce allelopathins towards the end of the growing season, whereas perennials did so during the growing season."

4.03

no evidence

4.04

Bourke, C. A. (1997) Effects of Hypericum perforatum (St. John's wort) on animal health and production. Plant Protection Quarterly, 1997, Vol.12, No.2, pp.91-92, 11 ref.

AB: "Wort-infested pastures can halve per hectare carrying capacity, and some livestock will die because of grazing wort. Horses are more susceptible to hypericin toxicity than cattle, cattle more than sheep, and sheep more than goats, probably because of differences in liver enzyme metabolizing systems. The presence of skin pigment or a thick wool covering will reduce the photosensitizing effect of hypericin." [grazing animals don't seem to avoid St. John'r wort]

4.05

(1) Syrett, P. (1989) Hypericum perforatum L., St. John's wort (Clusiaceae). Technical Communication - CAB International Institute of Biological Control, 1989, No.10, pp.353-356, 15 ref.
(2) Pilegaard, K.; Ladefoged, O. (1999) Wild plants that can cause poisoning in farm animals. [FT: Vilde planter som kan forarsage forgiftning hos produktionsdyr.] Dansk Veterinaertidsskrift, 1999, Vol.82, No.15, pp.666-668, 14 ref.

(1) AB: "The weed contains hypericin which causes photosensitivity in sheep and cattle."
(2) AB: "Descriptions are given of 4 wild plants that have become more abundant in Denmark and have caused poisoning of farm animals in neighbouring countries. The plants are Eastern groundsel (Senecio vernalis ), black nightshade (Solanum nigrum ), bog asphodel (Narthecium ossifragum ) and common St John's wort (Hypericum perforatum )."

4.06

no evidence

4.07

(1) Lewis, W. H. (1982) Plants for man: their potential in human health. Canadian Journal of Botany, 1982, Vol.60, No.4, pp.310-315, 23 ref.
(2) Schempp, C. M.; Winghofer, B.; Lüdtke, R.; Simon-Haarhaus, B.; Schöpf, E.; Simon, J. C. (2000) Topical application of St John's wort (Hypericum perforatum L.) and of its metabolite hyperforin inhibits the allostimulatory capacity of epidermal cells. British Journal of Dermatology, 2000, Vol.142, No.5, pp.979-984, 24 ref.

(1) AB: "Hypericum perforatum (which can cause allergic reactions in previously sensitized individuals)"
(2)AB: H. perforatum is a traditional herbal medicine that is used for the topical treatment of superficial wounds, burns and dermatitis.  [allergy on human seems rare]

4.08

no evidence

4.09

Plants for a Future, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, England Telephone Bodmin (+44 1208) 873554 Website: www.pfaf.org <http://www.comp.leeds.ac.uk/cgibin/pfaf/arr_html?Hypericum+perforatum&CAN=LATIND>

It can grow in semi-shade (light woodland) or no shade.

4.1

Plants for a Future, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, England Telephone Bodmin (+44 1208) 873554 Website: www.pfaf.org <http://www.comp.leeds.ac.uk/cgibin/pfaf/arr_html?Hypericum+perforatum&CAN=LATIND>

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils.

4.11

perrennial herb

4.12

perrennial herb

5.01

terrestrial

5.02

perrennial herb; Clusiaceae

5.03

no evidence

5.04

http://www.montana.edu/wwwpb/pubs/mt9810.pdf

"St. Johnswort is a taprooted perennial. The taproot may reach depths of 4 to 5 feet. Lateral roots grow 2 to 3 inches beneath the soil surface but may reach depths of 3 feet."

6.01

no evidence

6.02

Balvochyute, Ya. P.; Dagite, S. Yu. (1986) Studies on the seed biology and raw material quality of Hypericum perforatum. Lekarstvennye Rasteniya - Narodnomu Khozyaĭstvu. Tezisy Respublikanskogo Soveshchaniya, Kaunas, 16-17 Sentyabr., 1986, pp.12-13

AB: "Laboratory germination of seeds during the first 3 years was 84-94.4% but after a 3-year storage both the germination rate and energy markedly decreased. "

6.03

Mártonfi, P.; Repcák, M.; Mihoková, L. (1996) Hypericum maculatum Crantz subsp. maculatum x H. perforatum L. (Hypericaceae): corroboration of natural hybridization by secondary metabolite analysis. Folia Geobotanica et Phytotaxonomica, 1996, Vol.31, No.2, pp.245-250, 21 ref.

AB: "natural pentaploid hybrid H. maculatum subsp. maculatum x H. perforatum"

6.04

Matzk, F.; Meister, A.; Brutovská, R.; Schubert, I. (2001) Reconstruction of reproductive diversity in Hypericum perforatum L. opens novel strategies to manage apomixis. Plant Journal, 2001, Vol.26, No.3, pp.275-282, 17 ref.

AB: "facultative apomictic species Hypericum perforatum"

6.05

Matzk, F.; Meister, A.; Brutovská, R.; Schubert, I. (2001) Reconstruction of reproductive diversity in Hypericum perforatum L. opens novel strategies to manage apomixis. Plant Journal, 2001, Vol.26, No.3, pp.275-282, 17 ref.

AB: "facultative apomictic species Hypericum perforatum"

6.06

Briese, D. T. (1997) Population dynamics of St. John's wort in south-eastern Australia. Plant Protection Quarterly, 1997, Vol.12, No.2, pp.59-63, 15 ref.

"Generally, infestation densities were maintained by vegetative reproduction from lateral roots. The proportion of crowns originating from roots rather than seed ranged as high as 67–91% at individual sites."; "The principal unit used for population estimates was the crown rather than the plant, as St. John's wort can reproduce clonally and a single plant may consist of several crowns with connecting roots."

6.07

Dragland, S. (1996) Trial cultivation of St. John's wort (Hypericum perforatum L.). [FT: Provedyrking av prikkperikum (Hypericum perforatum L.). ] Norsk Landbruksforsking, 1996, Vol.10, No.3/4, pp.175-179, 11 ref.

AB: "the average total dry weight of leaves, stems and flowers was 180 g/m2 in the first year."

7.01

(1) Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.
(2) http://www.montana.edu/wwwpb/pubs/mt9810.pdf

(1) AB: "Originally introduced for ornamental or medicinal purposes the sp. has now spread to many locations, occurring on hillsides, roadsides, river banks, railways and pasture lands."
(2) "The sticky capsules adhere to animals and humans who travel from place to place, spreading the seeds."

7.02

Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.

AB: "Originally introduced for ornamental or medicinal purposes"

7.03

no evidence

7.04

no evidence

7.05

no evidence

7.06

no evidence

7.07

http://www.montana.edu/wwwpb/pubs/mt9810.pdf

"The sticky capsules adhere to animals and humans who travel from place to place, spreading the seeds."

7.08

Grigas, A. (1987) Viability of seeds after having gone through the digestive tract of cattle. Lietuvos Darbo Raudonosios Veliaos Ordino Zemdirbystes Mokslino Tyrimo Instituto Darbai, Agronomija, 1987, No.35, pp.165-175

AB: "Seeds of Hypericum perforatum were completely digested. "

8.01

Briese, D. T. (1997) Population dynamics of St. John's wort in south-eastern Australia. Plant Protection Quarterly, 1997, Vol.12, No.2, pp.59-63, 15 ref.

"annual seed production can be extremely variable from 0-200,000 per square meter"

8.02

Chabrerie, O.; Alard, D.; Touzard, B. (2002) Diversity of the vegetation and the soil seed bank in a chalk grassland in northwestern France. [FT: Diversité de la végétation et du réservoir de graines du sol dans une pelouse calcicole du nord-ouest de la France.] Canadian Journal of Botany, 2002, Vol.80, No.8, pp.827-840, many ref.
(2) Campbell, M. H. (1985) Germination, emergence and seedling growth of Hypericum perforatum L. Weed Research, UK, 1985, Vol.25, No.4, pp.259-266, 19 ref.

(1) AB: "seed bank was mainly dominated by opportunistic annual or biennial species (Hypericum perforatum , Blackstonia perfoliata )"
(2) AB: "Germination of H. perforatum seeds 1-6 months old was restricted by high temp. (16h/8h, 20/30 deg C), darkness and a chemical inhibitor in exudate from the capsule, whereas germination of 9-year-old seeds was only restricted by the inhibitor."

8.03

Campbell, M. H.; Delfosse, E. S. (1984) The biology of Australian weeds. 13. Hypericum perforatum L. Journal of the Australian Institute of Agricultural Science, 1984, Vol.50, No.2, pp.63-73, 66 ref.

1.68 kg glyphosate/ha or picloram + 2,4-D ester provided better long-term control than 2,4-D ester when applied in Feb. or May; picloram + 2,4-D ester was more effective than 2,4-D ester in Aug. and equally effective in Nov.; 2,4-D ester applied at early flowering or glyphosate applied in summer or autumn provided the best selective control in pastures.

8.04

Briese, D. T. (1996) Biological control of weeds and fire management in protected natural areas: are they compatible strategies? Biological Conservation, 1996, Vol.77, No.2/3, pp.135-141, 24 ref.

AB: "The fires both promoted development of the weed (H. perforatum) population and retarded that of the control agent. However, a subsequent indirect effect of fire was to favour population build-ups of C. quadrigemina and a recently released agent, Aphis chloris , through increased plant nutrient levels."

8.05

Recent introductions for biological control in Hawaii - 17.
AU: Davis, C. J.
AA: State Dep. of Agric., Honolulu, Hawaii.
SO: Proceedings of the Hawaiian Entomological Society, 1972, Vol.21, No.2, pp.187-190, 1 ref.

AB: " Hypericum perforatum. The gall midge Zeuxidiplosis giardi was active all the year round and has been responsible for a spectacular reduction of this weed."