Penny cress: declared pest

Page last updated: Wednesday, 29 April 2020 - 5:22pm

Please note: This content may be out of date and is currently under review.

Penny cress (Thlaspi arvense) is a declared pest in Western Australia (WA). This article describes the nature of the plant with links to requirements land owners/occupiers must adhere to and pest control methods.

Form: herbaceous — annual

Status: present in WA

Appearance

Winter growing annual, hairless, bright green plant with an unpleasant odour when plant is crushed. Native to Europe.

Stems: Erect 18-80cm tall, single or branched higher up in the plant.

Leaves: Alternate, basal leaves narrow, egg shaped attached to the stems by stalks, middle and upper leaves are oblong, entire or irregularly toothed, attached directly to the stem, that is no stalks (petioles), clasping the stem with two lobes 1-1.5mm long.

Flowers: At first in a small flat cluster at top of leafy stem, with flower stems becoming elongated when in fruit. Four sepals and four white petals 3-4mm long. Petals twice as long as sepals. Stamens six with two shorter than the others.

Seeds: Pod two-celled, carried on slender upward curving stalks, bright green to yellowish to greenish orange as seed ripens. Almost circular 1.25cm across strongly flattened and winged. Each wing contains four to 16 seeds. Seeds egg shaped and 1.2-2.3mm long and 1-1.5mm wide, reddish or purple/brown to black, somewhat flat with several concentric rings resembling a finger print.

Declared pest category

The Western Australian Organism List (WAOL) contains information on the area(s) in which this pest is declared and the control and keeping categories to which it has been assigned in Western Australia (WA). Use the links on this page to reach penny cress in WAOL.

Requirements for land owners/occupiers and other persons

Requirements for land owners/occupiers and other persons if this pest is found can be sourced through the declared plant requirements link.

Search > detect > report

Report: this pest to the Pest and Disease Information Service using the contact details given below or by using the MyWeedWatcher smartphone and tablet application or online reporting tool.

Control method

Control methods for this declared plant can be found through the penny cress control link.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080