Soldier thistle (Picnomon acarna) – introduced from the Mediterranean – competes with crops, damages machinery and can injure animals.
- erect plant to 1m
- leaves and stems are covered with fine white hairs and yellow spines 1-1.5cm
- stems are densely leafy and branched
- flower heads are 2-4cm and pink or purple, they can be solitary or in groups at the end of branches
- seeds are 4-6mm long, smooth and shiny with bristles at one end.
Why is it a problem?
- competes with crops
- chokes harvesting equipment
- sharp spines injure animals and reduce available grazing area.
- Eyre Peninsula – isolated plants
- Northern pastoral – found along some roadsides
- Northern agricultural districts and Yorke Peninsula – common in the southern areas of the region
- Murray Mallee – widespread
- South East – scattered infestations in the north
- Central region – scattered in the cereal growing areas.
- seeds germinating after autumn rains develop into large rosettes during winter
- rosettes produce erect stems by late spring; late germinating seedlings can produce stems with hardly any leaves
- flowering occurs over summer and the plants die by autumn.
How it spreads
- wind is the main method of dispersal; seeds can be blown short distances, and whole plants can be blown around after breaking off at the base
- seeds can also be carried on animals, vehicles and in water.