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Scientific Name
Synonyms
Family
Common Names
Origin
Cultivation
Naturalised Distribution
Habitat
Habit
Distinguishing Features
Stems and Leaves
Flowers and Fruit
Reproduction and Dispersal
Environmental Impact
Legislation
Management
Similar Species
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Click on images to enlarge

infestation (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

stems and leaves (Photo: Sheldon Navie)

close-up of stem with branches in opposite pairs at an angle of about 45° (Photo: Sheldon Navie)

close-up of leaf undersides showing small oil glands (Photo: Sheldon Navie)

flower clusters (Photo: Trevor James)

yellow flowers with numerous stamens (Photo: Sheldon Navie)

close-up of flower showing small black dots along the edges of the petals (Photo: Trevor James)

immature fruit (Photo: Sheldon Navie)

close-up of immaturre fruit (Photo: Trevor James)

close-up of seeds (Photo: Steve Hurst at USDA PLANTS Database)

the similar native small St. John's wort (Hypericum gramineum), has smaller leaves and flowers (Photo: Sheldon Navie)

the similar native matted St. John's wort (Hypericum japonicum), has smaller leaves and flowers and creeping stems (Photo: Sheldon Navie)

Hypericum perforatum

Scientific Name

Hypericum perforatum L.

Synonyms

Hypericum perforatum L. subsp. veronense (Schrank) H. Lindb.
Hypericum perforatum L. var. angustifolium DC.
Hypericum veronense Schrank

Family

Clusiaceae (Queensland, New South Wales, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)
Guttiferae (South Australia)

Common Names

common St. John's wort, common St. Johnswort, devil's flight, gammock, goatsbeard, goatweed, herb John, Klamath weed, Klamathweed, penny John, perforate St. John's wort, perforated St. John's wort, rosin rose, St John's blood, St John's grass, St. John's wort, St. Johnswort, Tipton weed, touch and heal, witch's herb

Origin

Native to most of Europe, the Azores, the Madeira Islands, the Canary Islands, north-western Africa (i.e. northern Algeria, Morocco and Tunisia), western and northern Asia (i.e. Saudi Arabia, Afghanistan, Cyprus, Iran, Iraq, Lebanon, Syria, Turkey, Armenia, Azerbaijan, Georgia, Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan and Mongolia), China and the Indian Sub-continent (i.e. northern Pakistan and India).

Cultivation

St. John's wort (Hypericum perforatum) is sometimes cultivated for use as a medicinal herb.

Naturalised Distribution

Widely naturalised in southern and eastern Australia. It is most common in eastern and southern New South Wales, the ACT, Victoria, south-eastern South Australia and south-western Western Australia. Less common or occasionally naturalised in other parts of South Australia and Western Australia, in Tasmania, and in south-eastern Queensland.

Also naturalised overseas in southern Africa, Japan, Hawaii, the Mascarenes, New Zealand, North America, the Caribbean and South America.

Habitat

This species is mostly found in upland temperate regions, but is occasionally also found in lowland areas and sub-tropical environments. It is a weed of pastures, open woodlands, grasslands, forest plantations, roadsides, railways, river banks and waste areas.

Habit

A long-lived (i.e. perennial) herbaceous plant usually growing 30-70 cm tall, but occasionally reaching up to 1.2 m in height. It normally produces several upright (i.e. erect) stems each year from a woody rootstock.

Distinguishing Features

Stems and Leaves

The stems are somewhat woody at the base and are branched mostly in their upper halves. These branches usually occur in opposite pairs at an angle of 45° to the main stem. Younger stems are hairless (i.e. glabrous), often reddish in colour, and have two lengthwise (i.e. longitudinal) ridges.

The relatively small leaves (5-30 mm long and 1.5-12 mm wide) are oppositely arranged, stalkless (i.e. sessile), hairless (i.e. glabrous) and light green in colour. They are egg-shaped in outline (i.e. ovate) to elongated (i.e. lanceolate) in shape and have entire margins. The leaves are dotted with numerous small oil glands which can be seen when held up to the light.

Flowers and Fruit

The bright yellow flowers (1-3 cm across) are borne in small clusters at the tips of the branches. These flowers have five elongated petals, often with small black dots along their edges, and numerous prominent stamens. Flowering occurs mostly during late spring and summer.

The fruit is a small capsule (5-10 mm long) containing numerous tiny seeds. These fruit are green and sticky when young, but turn reddish-brown or brown in colour and split open when fully mature. The seeds (about 1 mm long and 0.5 mm wide) are dark brown or blackish in colour, almost cylindrical in shape, and have a pitted or finely patterned (i.e. reticulate) surface.

Reproduction and Dispersal

This species reproduces by seed and also via creeping underground stems (i.e. rhizomes).

Seeds are dispersed by water, animals, vehicles and wind. They may also be transported in mud, soil and contaminated agricultural produce. Localised spread of colonies also occurs via the rhizomes, which can also be dispersed some distance during cultivation or other activities that disturb the soil.

Environmental Impact

St. John's wort (Hypericum perforatum) is regarded as a significant environmental weed in Victoria and as an environmental weed in the ACT, New South Wales, South Australia and Western Australia. It is actively managed by community groups in Victoria, New South Wales and the ACT, and is listed as a priority environmental weed in six Natural Resource Management regions.

Legislation

This species is declared under legislation in the following states and territories:

Management

For information on the management of this species see the following resources:

Similar Species

St. John's wort (Hypericum perforatum) is similar to Canary Island St. John's wort (Hypericum canariense), St. Peter's wort (Hypericum tetrapterum), tangled hypericum (Hypericum triquetrifolium) and the native small St. John's wort (Hypericum gramineum) and matted St. John's wort (Hypericum japonicum). These species can be distinguished by the following differences: