Quick Facts

Quick facts

• Golden Thistle (Scolymus hispanicus), a native of the Mediterranean, is a yellow flowered perennial herb with a large underground tuber and spiny leaves.
• The spines are known to injure the mouth of stock if consumed and the leaves, stalks and seeds can contaminate wool.
• It is a threat to agricultural production due to the ability to form thick impenetrable clumps.
• Golden Thistle is a drought tolerant weed.
• Management requires manual removal of the whole plant and tubers or herbicide use.

What Does It Look Like?

What is it?

Golden Thistle (Scolymus hispanicus) is an upright branching perennial herb that can grow up to 90 cm tall. It has a robust parsnip-like tap root which can extend 60 cm into the soil. The stems are multiple and slender produced from a crown. There are two distinct types of leaves. The leaves on the stems are spiny and deeply divided extending along the stem with spiny wings. The rosette leaves are clustered around the base of the plant in a radial pattern and are less ridged and spiny. The leaves have a variegated pattern created by the lighter colourings of the leaf veins. The stems, leaves and taproot all produce a milky sap when broken.

Golden thistle has golden-yellow florets on solitary flower heads of 2.5 to 4cm in diameter. They develop on very short stalks in the leaf axils with each head surrounded by a few very stout, spiny bracts (Agriculture Victoria 2021).

The seeds (achenes) are flat and about 7 mm long and 5 mm wide with a membranous margin (Harden 1992; Parsons & Cuthbertson 2001).

For further information and assistance with identification of Golden Thistle contact the herbarium in your state or territory.

Flower colour

Yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Golden Thistle originated in the Mediterranean and prefers a warm temperate environment with dry soils. Soil type can range from poor gravels to fertile alluvial loams (Parsons & Cuthbertson 2001).

Are there similar species?

This species is not commonly mistaken for but is similar to Spotted Thistle (Scolymus maculatus). By contrast Spotted Thistle is an annual rather than a perennial and can be identified by the white bony thickened margins on its leaves and stem wings (Auld & Medd 1987).

Why Is It A Weed?

What are its impacts?

Golden Thistle impacts on livestock as the numerous spines can damage the mouth area of animals if consumed (Parsons & Cuthbertson 2001).

Agriculture: Agricultural impacts include the contamination of wool by dead plant material and seed as well as the loss of grazing land. Grazing land is reduced through the formation of spiny impenetrable clumps which exclude stock and other activities from areas (Darby et al. 1999; Parsons & Cuthbertson 2001).

Native ecosystems: Golden Thistle impacts on the environment by providing cover for feral animals, such as rabbits, through the formation of spiny impenetrable clumps (Parsons & Cuthbertson 2001). The environmental impacts of rabbits include competition with native wildlife, damage to native vegetation and erosion of the soil (DEH 2004).

How does it spread?

Golden Thistle is dispersed predominantly by wind. The above ground section becomes brittle and breaks loose at the base. The wind then cartwheels, or 'tumble weeds', it along the ground shaking seeds out as it moves. Sheep and livestock can also transport seeds in their wool and fur (Parsons & Cuthbertson 2001). Golden Thistle can vegetatively spread through the transportation of the tubers (Parsons & Cuthbertson 2001). This is of concern when cultivation machinery, such as ploughs, are being used as tubers have the potential to 'hitch hike' to clean agricultural areas (Darby et al. 1999).

What is its history in Australia?

Considered as a garden escape from Toorak in Melbourne in 1901, Golden Thistle may have been imported for culinary purposes (Parsons & Cuthbertson 2001). The young shoots are edible and were used by the Ancient Greeks. This species is still harvested in Europe today (Auld & Medd 1987; Nuez & Hernández Bermejo 1994; Parsons & Cuthbertson 2001).

Golden Thistle is also recorded from the early 1900s along a Loddon river tributary between Campbelltown and Smeaton in Victoria. This area is still the site of a major infestation (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Physical control: Small infestations of Golden Thistle can be managed by manual removal (grubbing) of the plant, especially the tuber (Parsons & Cuthbertson 2001; Darby et al. 1999).

Mechanical control: Ploughing can be effective if carried out several times. Care needs to be taken to clean all machinery used as tubers can 'hitch hike' and infest clean sites (Darby et al. 1999). Slashing or mowing is not effective as above ground vegetation will re-grow from the tuber (Darby et al. 1999).

Grazing: Research indicates that goats may be a useful tool for thistle management in grazing pasture. Goats will consume the flowering stems of some thistle species when sheep are unable. However, this process has not been tested specifically for Golden Thistle (Holst & Allan 1996).

Chemical control: When the infestation is larger, or in difficult terrain, herbicide can be effective if used within a two year program when the plant is in the rosette stage (Parsons & Cuthbertson 2001).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Seeds of Golden Thistle germinate in autumn, winter and spring with flowers developing in late spring and summer. The tuber remains alive even though the above ground portion may die in summer. This tuber will produce new growth in the autumn (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

NSW, VIC

What areas within states and territories is it found?

Golden Thistle occurs in Victoria and New South Wales (Parsons & Cuthbertson 2001). Major infestations occur in north central Victoria around the Loddon River. Its distribution also extends into parts of central and southern Victoria as well as south western and central areas of NSW (Parsons & Cuthbertson 2001; Darby et al. 1999)

Where does it originate?

Golden Thistle is originally from the Mediterranean and Europe. Within its native range it can be considered a weedy species in dryland pasture and vineyards (Auld & Medd 1987; Parsons & Cuthbertson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, VIC, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Scolymus hispanicus

Other scientific names (synonyms)?

Does it have other known common name(s)?

Spanish Salsify, Spanish Oyster Plant (Europe), Sunnariah (Lebanon), Common Goldenthistle (USA)