Pest plant - Hoary cress
Hoary cress plant in flower
Hoary cress (
) is a perennial weed easily spread across paddocks by cultivation.
erect perennial weed to 75cm
leaves and stems are blue-green with fine white hairs
first leaves form a rosette at ground level, are wedge shaped and up to 10cm
erect stem develops later and has smaller, oval leaves
flowers are white in colour with 4 petals, 4-6mm wide, arranged in dense groups on fine stalks at the top of the stem
fruit is a 2-4mm heart-shaped capsule, with 1-2 reddish brown seeds, 2mm long
taproot can be 2 metres deep, with many horizontal branching roots.
Why is it a problem?
reduces the yield of cereal and interferes with harvesting
if eaten by stock, it taints meat and milk and may be poisonous in larger quantities.
Eyre Peninsula – isolated infestations on lower and eastern EP
Northern pastoral – sparse in marginal country, not present elsewhere
Northern agricultural districts and Yorke Peninsula – scattered infestations
Murray Mallee – isolated outbreaks
South East – isolated outbreaks
Central region – very isolated patches.
deep-rooted perennial that reproduces by suckering from rootstocks or by seed
seeds germinate in autumn, new growth occurs from the crown and root buds in autumn, stems grow over winter
plant flowers September-November.
How it spreads
a single plant can produce 1000-5000 seeds with 80% viability
main method of dispersal is root fragments moved by cultivation.
Pest plants (web page)