Scotch thistle - Onopordum acanthium (Care, Characteristics, Flower, Images)

Scotch thistle

Also known as: Scottish thistle

Scotch thistle (Onopordum acanthium) is considered to be a noxious weed in many parts of the world. Dense colonies of this plant interfere with animals' ability to graze and limit their access to water. However, its large blooms and unique leaves have led some people to grow it ornamentally.

Scientific classification

Species

Scotch thistle (Onopordum acanthium)

Asters bellflowers fanflowers and allies

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Biennial, Annual, Perennial

Lifespan

Herb

Plant Type

1 m

Spread

Silver, Gray

Leaf Color

2.5 cm to 8 cm

Flower Size

Purple, Pink

Flower Color

Green, Gray, Silver

Stem Color

Evergreen

Leaf type

20 - 35 ℃

Ideal Temperature

Images of Scotch thistle

Distribution of Scotch thistle

Distribution Map

Scotch thistle flourishes in a variety of temperate environments across the Eurasian continent, including parts of Eastern, Western, Northern, and Southern Europe, as well as areas within Western and Central Asia. Though native to these regions, its presence spans several other parts of the world. Specifically, scotch thistle has been introduced to areas in South America, the Baltics, and Oceania. Within some of these new territories, such as Australasia and parts of South America, scotch thistle is sometimes thought to have an impact on local ecosystems, owing to its adaptive qualities and vigorous growth.

Native

Cultivated

Invasive

Introduced

No species reported

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Habitat

Dry pastures, Disturbed fields

Hemisphere Trend Curve

Northern

Sorthern

Weed Control

Scotch thistle(Onopordum acanthium) is native to Europe and Asia. It's sometimes grown as an ornamental plant and otherwise grows in land which is usually uninhabitable, such as arable land or chalky soil and prefers dry heat - such as many parts of Mediterranean. It's known to spread rapidly and is a well-known weed.

How to Control It

For optimal control of scotch thistle, it's best to remove the plant in spring, before it starts flowering. This prevents the plant from producing seeds and spreading further.

Hand-pulling: Wearing a thick pair of gloves to protect your hands from its prickly spines, grip the scotch thistle at the base and pull gently but firmly upwards to remove the whole plant, including the root. Dispose of the plant carefully to avoid any seeds spreading.
Hoeing: Use a sharp hoe to sever the stem of scotch thistle from its root. This should be done on a hot day so that the disconnected stem and leaf will dry out and die.
Covering: Spread a thick layer of organic mulch or landscape fabric around the base of the scotch thistle plant. This will block sunlight and prevent photosynthesis, causing the plant to weaken and die.
Biological control: Use a specific approved insect, like the Thistle-chewing Weevil (Rhinocyllus conicus), to eat the plant and reduce its growth. It's important to consult with a local extension service before introducing these insects to ensure they won't become a pest themselves.
Vinegar spray: Fill a spray bottle with vinegar and spray directly onto the scotch thistle. The acid in the vinegar will burn the plant and cause it to die. Always be careful not to spray on desirable plants close to the scotch thistle as the vinegar can damage them too.

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Care Guide for Scotch thistle

Every week

Water

Full sun

Sunlight

20 - 35 ℃

Ideal Temperature

Garden Soil

Soil Type

Water: Scotch thistle thrives in temperate regions and is drought-tolerant, requiring weekly watering for optimal health in cultivation. Consistent soil moisture during its growing season supports robust growth and a vibrant floral display, making it suitable for outdoor environments.

Fertilize: For scotch thistle, use a high phosphorus fertilizer to enhance root growth and flowering, applying it sparingly at the start of the growing season and during budding. Monitor soil fertility, as over-fertilization can hinder growth. Less fertilizer often maintains scotch thistle's natural vigor effectively.

Propagation: Scotch thistle is a biennial thistle native to Europe and Asia, thriving in sunny, well-drained areas. Directly sow seeds for propagation, as it does not transplant well. Ensure soil contact and moisture without waterlogging. Once established, scotch thistle can self-seed prolifically if unmanaged.

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