What is St John's wort?
- St John's wort is a weed of pastures, open bushland and roadsides.
- St John's wort is a
declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of St John's wort are prohibited in Tasmania.
How to identify St John's wort
John's wort is a perennial (long-lived) herb growing to between 30 and
70 cm and occasionally to 1.2 metres high. The reddish stems arise from
the rootstock or woody crown.
- St John's wort has a main root
extending to 1 metre deep and horizontal rhizomes (underground stems)
just below the surface producing buds from which new above-ground growth
develops each year.
- The leaves are stalkless and hairless and
have numerous small oil glands that give the leaf a perforated
appearance when held up to the light. The flowers are bright yellow with
black glands dotted along the margins of the petals, and grow in
numerous clusters at the end of the branches. The fruit is a sticky
capsule containing numerous, dark brown or black cylindrical seeds.
related weed, square-stemmed St John's wort (also called St Peter's
wort) is similar to St John's wort, but stems are almost square in
cross-section, and the leaves are oval to oblong, often heart-shaped,
and stem clasping at the base.
- For further help in identifying St John's wort, search the
Dennis Morris Weeds and Endemic Flora database
for St John's wort illustrations. If you are still in doubt about the
weed you are dealing with, contact your Regional Weed Management Officer
on 1300 368 550 for help.
Image top: St John's wort (K Stewart)
Image above left: St John's wort (K Stewart)
Image above right: St John's wort (K Stewart)
St John's wort in Tasmania
- St John's
wort occurs as a localised weed of roadsides, poorly managed grazing
land, neglected areas and disturbed bushland areas of Tasmania,
particularly in the northern Midlands, north-east, central north coast
and the south east (see map).
John's wort is a threat to the grazing industry due to its toxicity to
stock, and its ability to compete with desirable pasture species in
poorly managed pastures.
- St John's wort is also an
environmental weed and can out-compete native species, with open
grassland-woodland communities most affected.
What is the legal status of St John's wort in your area?
- The legal responsibilities of landholders and other stakeholders in dealing with St John's wort are laid out in the
Statutory Weed Management Plan for St John's Wort.
Table 1 (Zone A municipalities) in the Statutory Weed Management Plan
to find out whether your area falls in an eradication or containment
Detailed management and control guidelines for St John's wort can be found in the
St John's Wort Control Guide. Refer also to
Herbicides for St John's Wort Control. For further information see
DPIPWE's Weed Links and Resources.
St John's Wort Control Guide
Herbicides for St John's Wort Control
Statutory Weed Management Plan for St John's Wort
Weed Links and Resources
Other useful links
Weeds in Australia - Weed Management Guide
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