Taxonomic name: Hypericum perforatum (Linnaeus)
Synonyms: Hypericum officinale (Gater), Hypericum perforatum var. perforatum, Hypericum perforatum var. angustifolium, Hypericum perforatum var. microphyllum, Hypericum perforatum var. veronense, Hypericum veronense, Hypericum vulgare (Bauhin)
Common names: äkta johannesört (Sweden), äkta mannablod (Sweden), amber (USA, UK), bassant (France), binbirdelikotu (Turkey), Blutkraut (Germany), casse-diable (France), castellas (South America, Spain), common St Johnswort (USA, UK), common St. John's wort (USA, UK), corazoncillo (South America, Spain), eala bhuidhe (Ireland), Echtes Johanniskraut (Germany), gammock (USA, UK), Gemeines Johanniskraut (Germany), goatsbeard (USA, UK), goatweed (USA, UK), Hartheu (Germany), herb john (USA, UK), herbe De Saint-Jean (France), herbe de St. Jean (France), hierba de San Juan (South America, Spain), hipérico (South America, Spain), iperico (Italy), johannesblöda (Sweden), Johanneskruid, johannesört (Sweden), Johanniskraut (Germany), klamathweed (USA, UK), läpikuisma (Finland), lule gjaku (Albania), lulebasan (Albania), lulemaji (Albania), mäkikuisma (Finland), mansblod (Sweden), millepertuis (France), millepertuis perfore (France), penny john (USA, UK), perforate St. John's wort (USA, UK), racecourse weed (Australia), randpirk (Sweden), rosin rose (USA, UK), St. John's grass (USA, UK), St. John's wort (USA, UK), tipton weed (USA, UK), todabuena (South America, Spain), touch and heal (USA, UK), Tüpfel-Hartheu (Germany), Tüpfel-Johanniskraut (Germany), Unserer Frauen Bettstroh (Germany), Y fendigedig (Wales)
Organism type: herb
Hypericum perforatum, more commonly known as St. John's wort, is a native flowering perennial plant of Eurasia. It has been widely introduced, mainly by human vectors, to North and South America, parts of Africa, Australia and New Zealand. St. John's wort can survive in a wide range of environments and has the ability to store reserves in its root crown and compensate during harsh times, which makes this plant difficult for management control. In recent years Hypericum perforatum has gained media attention for its use in alternative medicine, mainly for treating depression.
St. John's wort is a perennial herb with two distinct growth phases, a fall/winter prostrate or basal growth, and a spring/summer erect woody stem growth (Gordon & Kluge, 1991). St. John's wort has an underground rhizomatous stem and deep taproot with many lateral roots (Krueger & Sheley, 2002). The erect vegetative growth has opposite, sessile, entire (ANHP, 2005), linear to elliptical leaves 10-30mm long and 3-16mm wide, with translucent glands located on the undersides of the leaf and black glands located along the leaf margins (PIER, 2003). The flowers are numerous, paniculate cymes with 5 yellow petals, 5-8mm long, black dotted along the margins as well (PIER, 2003). Multiple stamens cluster into three groups, with three styles present (PIER, 2003). The capsules are 7-8mm long, dark brown ovoid, three chambered (ANHP, 2005), holding thousands of small, pitted cylindrical seeds (PIER, 2003).
Hypericum spp., Hypericum canariense, Hypericum mutilum
agricultural areas, natural forests, planted forests, range/grasslands, ruderal/disturbed, scrub/shrublands, urban areas
Hypericum perforatum forms dense stands on recently disturbed sites from impacts like mining, fire, logging, construction, etc. (Tisdale et al. 1959). It also establishes itself in waste grounds, roadsides, pasture, rangeland, and open woodland (Buckley et al. 2003). It has adapted to a wide range of environmental conditions in its native and introduced range (Maron et al. 2004). H. perforatum can tolerate a variety of soils, from dry, rocky, shallow soils, to deep fertile soils, with it performing best in regions with greater than 760mm of precipitation a year (Buckley et al. 2003). Soil pH tolerance ranges from 4.3-7.6 (ANHP, 2005). It can tolerate drought and disturbance conditions by storing reserves in its root crown (Buckley et al. 2003).
St. John's wort establishes itself on recently disturbed sites (Tisdale et al. 1959) and displaces and inhibits the settlement and establishment of native flora (Briese & Jupp, 1995). The plant contains two primary toxic compounds hypericin and hypericum red, which can cause photosensitivity in grazing livestock, leading to loss of weight and condition, even death in rare circumstances (Tisdale et al. 1959). The dried stems that are present during the fall and winter can pose as a fire hazard for forest and range lands (ANHP, 2005).
St. John's wort has become popular in the 1990s as a herbal remedy, mainly for the treatment of depression. In preliminary clinical studies 50%-80% of people suffering from mild to moderate depression showed improvement (Rey & Walter, 1998). Other potential medical applications using St. John's wort includes treatments for anxiety, sleep disorders, bacterial and viral infections, inflammatory arthritis, skin wounds, cancer, and certain respiratory conditions (Rey & Walter, 1998). The plant is collected from the wild, but with its increasing popularity, it has begun to be cultivated. In Russia the plant is also used to flavour a traditional soft drink, "Baikal" (Kireeva et al. 1999).
Native range: United Kingdom, Europe, Russian Federation, China, India, Western Asia, Middle East, North Africa (GBIF, 2005; USDA-GRIN, 2004)
Known introduced range: North America, South America, Central America, West Indies, Australia, Japan, New Zealand, South Africa, Mascarene Islands, Papua New Guinea (PIER, 2003; GBIF, 2005; USDA-GRIN, 2004)
Introduction pathways to new locations
For ornamental purposes: Hypericum perforatum was introduced into Australia in the middle of the 19th century for its ornamental and medicinal properties (Briese & Jupp, 1995).
People sharing resources: St. John's wort was introduced into South Africa in 1942 from a contaminated batch of vetch seed (Gordon & Kluge, 1991).
Road vehicles (long distance): Seed capsules can adhere to vehicles transporting the seed long distances (Gordon & Kluge, 1991).
Local dispersal methods
Garden escape/garden waste: An introduction into Australia by a German woman resulted in the escape of the plant from her garden onto a local racehorse track where it continued to spread (Rey & Walter, 1998).
On animals: The seeds of St. John's wort have a sticky exudate on the surface which could lend to the transport of seeds on the fur or feet of animals (Tisdale et al. 1959).
On animals (local): Wind dispersal is not considered one of the main dispersal mechanism but still a possibility (Tisdale et al. 1959). According to Gordon and Kluge (1991), 95% of seeds from the parent plant fall within a 3 meter radius.
Other (local): Hypericum perforatum can reproduce vegetatively through suckers originating from the root crown of the parent plant (Tisdale et al. 1959). The suckers severe the connection to the parent plant soon after establishment (Tisdale et al. 1959).
Water currents: Water transport is considered a potential dispersal mechanisms of Hypericum perforatum (Tisdale et al. 1959).
Chemical: Chemical control of St. John's wort has had mixed results depending on the management plan and location of application. In South Africa, the initial management plan was a chemical eradication, however this programme was suspended when it proved unsuccessful and too expensive (Gordon & Kluge, 1991). Similarly, a chemical control in British Colombia, Canada, also was uneffective in eradicating the plant (Gordon & Kluge, 1991). However several field studies and programmes were initiated that designed a chemical application management strategy in the foothills and pasture lands of South Australia. Several different chemical formulations were used, but the ones that proved most successful were a combination of 2,4-D + 2,2,-DPA, or a straight application of glyphosate (Campbell et al. 1975). Timing of the applications is crucial in the success of a chemical application, with an autumn spraying seeming to be most effective in Australia (Campbell et al. 1975). In addition the method of application and the composition of the infested area prerequisite the chemical used. In a study by Campbell et al. (1991) found that triclopyr + picloram in combination were not selective for just St. John's wort but also killed any nearby legumes. A boom and spot method for application was discovered to work best with these chemicals. For glyphosates an aerial application worked better, and was more selective to St. John's wort, however glyphosates did not perform well at warmer temperatures (Campbell et al. 1991). For the best coverage using an aerial application adjuvants, water carriers, and repetitive anuual sprayings are recommended (Campbell et al. 1991). Ammonium sulfamate has been shown in several studies to be an effective herbicide against woody stem plants and St. John's wort, with the added benefit of decomposing into a plant soluble fertilizer for native grasses (Allgaier, 1944).
Cultural: Cultural management of St. John's wort has been in the form of controlled grazing by livestock (Campbell et al. 1975) but only as an additional means of control to other methods like a chemical or biological programme. It also msut be taken into consideration that St. John's wort is toxic and can cause neurological and other health problems, even death, if consumed in high quantities by livestock (Buckley et al. 2003). Goats seem to be more tolerant to the toxic effects of St. John's wort than other types of livestock (Buckley et al. 2003). Ploughing and fallowing on arable lands follwed by subsequent sowing of perennial grasses and legumes is another method of control (Campbell et al.1975). Sowing of perennial grasses and legumes a few weeks after a chemical application can help in suppressing any reemergence (Buckley et al. 2003).
Physical: Mechanical removal is not recommended for this species as it can vegetatively reproduce from the rhizomatous root crown which can be quite extensive underground (Tisdale et al. 1959). Fire is not recommended as a means of control since the plant can persist from underground resource storage in its crown(Buckley et al. 2003) and then reproduce through suckers (Tisdale et al. 1959).
Hypericum perforatum reproduces through flower and seed production, as well as vegetatively through suckers arising from an underground rhizome (Tisdale et al. 1959). Flower production occurs in the summer with capsules persisting from late summer to early fall when seeds are shed (Fox et al. 1999). Seed production is very high with an average infloresence producing 39,000 seeds (Gordon & Kluge, 1991). Suckers can arise from the parent plant typically after mechanical damage or disturbance and quickly separate previous connections to the parent plant (Tisdale et al. 1959).
St. John's wort initiates new erect stem growth and seed germination in spring (Tisdale et al.1959). Mean germination temperature needs to be above 11°C and access to light and adequate precipitation (Tisdale et al. 1959). Seed exhibits dormancy from exudation from the leaves and capsules (Tisdale et al. 1959), with a time of 4-6 months after harvest before germination (ANHP, 2005). Seed can remain viable in the soil between 6-10 years (Tisdale et al. 1959). Flower production occurs in the summer with leaves beginning to shed near the end of the flowering period, late summer to fall (Tisdale et al. 1959). Seeds are shed in fall and shoots begin to dieback in the winter (Fox et al. 1999); however basal growth can occur during the winter as well (Tisdale et al. 1959). The plant is a perennial reaching maturity in two seasons, with the first years growth directed mainly to establishment of the root system (Tisdale et al.1959).
Principal sources: Tisdale, E.W., Hironaka, M., & Pringle, W.L., Jan. 1959, Observations on the Autecology of Hypericum perforatum, Ecology, Vol. 40, No. 1, pp.54-62.;
Buckley, Y.M., Briese, D.T., & Rees, M., 2003, Demography and management of the invasive plant species Hypericum perforatum. I. Using multi-level mixed-effects models for characterizing growth, survival, and fecundity in a long-term data set, Journal of Applied Ecology, Vol. 40, pp. 481-493;
Gordon, A.J., & Kluge, R.L., 1991, Biological control of St. John's Wort, Hypericum perforatum (Clusiaceae), in South Africa, Agriculture, Ecosystems, and Environment, Vol. 37, pp.77-90.
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Tuesday, 7 August 2007