Hypericum perforatum L.

Title: Hypericum perforatum L.

Scientific Name: Hypericum perforatum L.

Common Name: St John's wort

Source & more images (via ALA)

Habitat: St. John's Wort is native to and relatively widespread in the temperate climes of Europe, western Asia, and North Africa. It was also introduced to other temperate climes. It prefers sunny locations on dry, limy or primary rocky soils and is found on fallow land, the edges of meadows and forests, walls, and paths up to an altitude of 1500 metres.

Distribution:


Present Distribution - Australia (source: ALA)		Present Distribution - USA (source: USDA)

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Seeds germinate in autumn, winter or spring. P & C (1992)

2. Establishment requirements? Would receive some shading where occurring as an environmental weed. Carr et al (1992)

3. How much disturbance is required? Is a ‘very serious’ weed of lowland grassland and grassy woodland, dry sclerophyll forest and woodland, damp sclerophyll forest and riparian vegetation. Carr et al (1992)

GROWTH / COMPETITIVE

4. Life form? Perennial herb. P & C (1992)

5. Allelopathic properties? None described. P & C (1992)

6. Tolerates herb pressure? “Stock eat St. John’s Wort only when other feed is scarce”. P & C (1992)

7. Normal growth rate? “Competes throughout the year with other species for light and nutrients and when firmly established, eliminates all other plants”. “Whilst St. John’s Wort once established, competes strongly with other plants, in itself is very sensitive to competition in the young stages”. P & C (1992 p. 391). P & C (1992)

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerant of frost and drought. P & C (1992)

REPRODUCTION

9. Reproductive system? Reproducing from crowns, rhizomes and by seed. P & C (1992)

10. Number of propagules produced? “Seed production is prolific and a single plant may produce 33,000 seeds in a season”. P & C (1992)

11. Propagule longevity? “Some seeds last at least 10 years in the soil but most germinate in the first few years”.

12. Reproductive period? Forms dense infestations. (Campbell et al 1995 p. 152)

13. Time to reproductive maturity? Plants generally do not flower in the first year.

DISPERSAL

14. Number of mechanisms? “Seeds are very small and readily dispersed in water, mud, soil and agricultural produce”. Cultivation can also spread pieces of rhizome. Seed capsules adhere to the wool and fur of animals. P & C (1992)

15. How far do they disperse? “The seed can be dispersed short distances by wind and long distances by man and water. (Parsons 1973)” - (Campbell et al 1995).

Impact Assessment

RECREATION

1. Restrict human access? “An erect perennial herb, commonly 30 to 70 cm high.” Minimal or negligible impact. Parsons, W.T. and Cuthbertson, E.G. (2001),

2. Reduce tourism? “St John’s wort forms extensive infestations excluding most other ground-flora.” Minor effects to aesthetics. Muyt (2001)

3. Injurious to people? It can cause, “a contact rash in some people.” Mildly toxic. Parsons, W.T. and Cuthbertson, E.G. (2001),

4. Damage to cultural sites? “St John’s wort forms extensive infestations excluding most other ground-flora.” Likely to have a moderate negative visual effect. Muyt (2001)

ABIOTIC

5. Impact flow? Terrestrial species. Parsons, W.T. and Cuthbertson, E.G. 92001),

6. Impact water quality? Terrestrial species. Parsons, W.T. and Cuthbertson, E.G. (2001),

7. Increase soil erosion? “Main roots are stout and extend to 1 m deep.” “St John’s wort forms extensive infestations excluding most other ground-flora.” Unlikely to contribute to soil erosion.Parsons, W.T. and Cuthbertson, E.G. (2001); Muyt (2001).

8. Reduce biomass? “It is considered to be a weed when it invades poorly managed grazing land, sparse bushland, roadsides, and neglected areas.” Dense infestations are likely to increase biomass.Parsons, W.T. and Cuthbertson, E.G. (2001),

9. Change fire regime? “In late summer, the dry stems constitute a fire hazard in forest areas.” Moderate increase in the frequency of fire risk.Parsons, W.T. and Cuthbertson, E.G. (2001),

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Plains grassy woodland (E); CMA=West Gippsland; Bioreg=Gippsland Plain; VH CLIMATE potential.
“St John’s wort forms extensive infestations excluding most other ground-flora and seriously impeding overstorey recruitment.” Major displacement of some species within different strata. Muyt (2001).

10(b) Impact on medium value EVC? EVC=Grassy dry forest (D); CMA=Goulburn Broken; Bioreg=Central Victorian Uplands; VH CLIMATE potential.
Impact as in 10(a) above. Muyt (2001).

10(c) Impact on low value EVC? EVC=Shrubby foothill forest (LC); CMA=Port Phillip; Bioreg=Central Victorian Uplands; VH CLIMATE potential.
Impact as in 10(a) above. Muyt (2001).

11. Impact on structure? “St John’s wort forms extensive infestations excluding most other ground-flora and seriously impeding overstorey recruitment.” Major effect on 20% of the floral strata. Minor effect on shrubs. Muyt (2001).

12. Effect on threatened flora?

FAUNA

13. Effect on threatened fauna?

14. Effect on non-threatened fauna? “It is invasive in various native habitats including grasslands, grassy woodlands and forests, with the largest infestations in north-east Victoria and southern and central NSW. St John’s Wort forms extensive infestations excluding most other ground-flora and seriously impeding overstorey recruitment.”

The plant is poisonous which can lead to loss of condition and eventually death. UNKNOWN. Muyt (2001).

15. Benefits fauna? No benefits

16. Injurious to fauna? “St John’s wort contains hypericin, which causes photosensitisation in any mammals that ingest it resulting in blisters on weakly pigmented parts of exposed skin.” UNKNOWN. Blood (2001).

PEST ANIMAL

17. Food source to pests? Not known as a food source to pest.

18. Provides harbor? Not known to provide harbor for pest animals.

AGRICULTURE

19. Impact yield? “In pastures, H. perforatum is a weed because it replaces useful vegetation to an extent that can lead to the abandonment of formerly productive areas.” The plant, “reduces milk yield and causes abortions in animals.” Groves et al (1995); Parsons, W.T. and Cuthbertson, E.G. (2001),

20. Impact quality? Not known to affect quality of agricultural production.

21. Affect land values? “In pastures, H. perforatum is a weed because it replaces useful vegetation to an extent that can lead to the abandonment of formerly productive areas.” Land value may be reduced significantly if no longer available for agriculture. Unknown – or minimal impact on land values. Groves et al (1995).

22. Change land use? In pastures, the plant can be readily controlled. “The greatest competition to the weed is provided by a mixture of subterranean clover and phalaris when sown on a prepared fallow. The developing pasture should be left ungrazed in the first year to allow the subterranean clover maximum chance to smother the St John’s wort.” Pasture is temporarily unavailable for grazing, however, no serious or permanent alteration of agricultural activity. Parsons, W.T. and Cuthbertson, E.G. (2001),

23. Increase harvest costs? Not known to affect harvest costs.

24. Disease host/vector? None evident.

Feedback

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of Friends of Grasslands.

Attachments:

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St Johns wort via ala.JPG

referenced by (1)

wra1033: Common Name - S (via St Johns wort)

Article: wra7101 (permalink)
Categories: :wra:h, :wra:inv1, :wra:invmh, :wra:inv2, :wra:inv3, :wra:inv4, :wra:invl, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:invm, :wra:inv9, :wra:invh, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impl, :wra:imp2, :wra:impml, :wra:imp3, :wra:imp4, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:impmh, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:impm, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imph, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 5 June 2012; 12:00:53 PM AEST

Author Name: David Low
Author ID: adminDavid