Tangled hypericum

Tangled hypericum (Hypericum triquetrifolium) is a State prohibited weed.

Tangled hypericum

If you find tangled hypericum

If you think you may have seen tangled hypericum, please contact us by:

Please do not attempt to treat or dispose of this weed yourself. We will treat, remove and dispose of tangled hypericum safely, at no cost to the land owner.

Why you must report tangled hypericum

Tangled hypericum is a very competitive plant with the ability to eliminate most other vegetation. It can be easily spread throughout a paddock and to new locations by contaminated cultivation equipment.

Although unconfirmed, it is suspected to be poisonous to stock. It has a very high potential to infest much of central Victoria.

It is native to Europe and the Mediterranean, and believed to have entered Victoria during the gold rush, where it has occurred at Tarnagulla since 1910. It can propagate by roots and rhizomes (underground stems) being spread by cultivation equipment and potentially also by seed.

Identifying tangled hypericum

Tangled hypericum is an erect perennial herb to 45cm tall with many tangled branches. It reproduces from rhizomes and seed. It could invade open woodlands and agricultural land.

Arrowhead-shaped leaves (5 to 15mm long) are arranged opposite each other along much-branched stems. Stems and leaves both have minute black glands, while only the leaves have translucent oil glands.

Short-stalked yellow flowers occur in clusters at branch ends in summer. Each flower (1 to 1.5cm wide) has 5 petals.

The fruit (3 to 4mm long) is a capsule with 3 compartments.

Flowering tangled hypericum plantThe flowers of tangled hypericumFlower of tangled hypericum

Lookalike species

It is closely related to the common weed St John's wort (H. perforatum), which tends to be taller (up to 1.2m) and has larger flowers (1 to 3cm).

Page last updated: 27 Mar 2024