Description:
Scotch thistle is an erect annual or biennial herb to 2 m high, commonly 1 to 1.2 m. Generally one main stem with numerous branches, covered with dense, appressed, woolly hairs giving it a whitish-grey appearance. It has broad spiny wings along the stems. The flower heads are purple and round with spiny bracts.
As A Soil Indicator:
Low Calcium, High Potassium. High Manganese, High Magnesium, Very low Iron, High Sulfate, High Boron, Low humus in the soil , Limited bacteria, Compacted soil , Poor drainage
Life cycle:
Annual or biennial. Seed germinate at any time with a flush of germination in late summer to early autumn or late winter to spring. Plants that germinate in late summer form sizeable rosettes before the onset of winter. Seedlings from late autumn or early winter may suffer a very high natural mortality.
Beneficial:
Apparently once cultivated as a medicinal plant for treating skin sores and ulcers. The roots, young shoots and flower buds were eaten as vegetables. Flowers can be used to make a ‘rennet’ to set cheese. Mineral accumulator 
Detrimental:
A weed of improved pastures, crops, fallows and disturbed areas. It is strongly competitive. Newly sown pastures are often overrun by Scotch Thistle in infested areas. It is too spiny to be readily grazed. Damages mouths and eyes of stock and contaminates wool.
Toxicity:
Not recorded as toxic

Download PDF

What to read next?