Milk thistle - Silybum marianum (Care, Characteristics, Flower, Images)

Milk thistle

Also known as: Variegated thistle, Lady's thistle, Marian thistle, Mary's thistle, Our lady's thistle, Mediterranean milk thistle

Milk thistle (Silybum marianum) is a biennial thistle that has white-mottled blossoms. The common name references the appearance of these blossoms, which look like they have been doused in milk. It grows up to 1.8 m tall. This species is often cultivated as an ornamental plant.

Scientific classification

Species

Milk thistle (Silybum marianum)

Asters bellflowers fanflowers and allies

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Toxic to Humans

Toxicity

Weeds

Weed or not

Biennial, Annual, Perennial

Lifespan

30 cm to 2 m

Plant Height

1.6 m

Spread

Green, White, Variegated

Leaf Color

5 cm to 8 cm

Flower Size

Black

Fruit Color

Purple, White, Pink

Flower Color

Green, White, Purple

Stem Color

Deciduous

Leaf type

20 - 35 ℃

Ideal Temperature

Images of Milk thistle

Distribution of Milk thistle

Distribution Map

Milk thistle, a thistle-like plant, is native to the Mediterranean basin and Western Asia, with a stable presence across Europe and parts of North Africa and the Middle East. It has been introduced to regions such as South America, North America, parts of Asia, and the Pacific, often adapting robustly in these areas. Milk thistle is cultivated in various regions, and in certain areas, it is sometimes thought to be mildly invasive, with the potential to impact local ecosystems. Its cultivation, however, is generally managed without significantly disrupting native flora and fauna.

Native

Cultivated

Invasive

Introduced

No species reported

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Habitat

Waste places, close to the sea

Hemisphere Trend Curve

Northern

Sorthern

Flowering

Fruiting

Culture

Garden Use

Milk thistle is rarely grown in gardens due to its invasive properties, but it is occasionally cultivated for its striking appearance. The plant is used in herb and flower gardens, where it provides interest during the growing season. Its tall, slender stalk allows it to stand above most other flowering garden plants, ensuring the bright-colored summer flowers are easily visible.

Symbolism

Strength, Protection, Hex Breaking

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Toxicity

Poisoning from milk thistle can cause severe allergic reactions, particularly in those sensitive to the Asteraceae family. Side effects from consuming seeds include nausea, vomiting, and diarrhea. People with diabetes or hormone-sensitive conditions are at increased risk due to blood sugar and estrogen level impacts.

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Weed Control

Milk thistle is native to the Mediterranean, Asia, and Russia. Today, it can be found throughout the Americas, Australia, New Zealand, Japan, and Africa. It is recorded as an invasive weed in over thirty-two countries, such as the United States of America, Belgium, Australia, and the United Kingdom. In these countries, it infests pastures where cattle graze. In Washington State, it has been identified as a noxious weed because its spines can harm cattle, and it is poisonous due to its high levels of nitrates. If necessary, the weed can be removed via mechanical control, removing flower heads, or chemical herbicides.

How to Control It

The best season to manage the growth of milk thistle is either in the late winter before it seeds or early spring. It should be controlled before it reaches the flowering stage to prevent seed spread.

Hand pulling: Wear gloves and pull milk thistle out by the roots on a wet day when the soil is loose.
Mulching: Place a thick layer of organic mulch around milk thistle to suppress growth and prevent seed germination.
Mowing: Regularly cut down milk thistle before it can flower and seed to limit its spread.
Plant competition: Cultivate other strong-growing plants nearby that can outcompete milk thistle for resources.
Biological control: Introduce natural milk thistle predators or pathogens to help keep its population in check without chemicals.

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Care Guide for Milk thistle

Every week

Water

Full sun

Sunlight

20 - 35 ℃

Ideal Temperature

Garden Soil

Soil Type

Water: Originating from dry soils, milk thistle is drought-tolerant and requires weekly watering to prevent over-saturation. Thriving in full sun and well-draining conditions, its water needs peak during the active growing season, highlighting the importance of adequate hydration for optimal growth and health.

Fertilize: Fertilize milk thistle bi-monthly with high phosphorus fertilizers to enhance root growth and flowering. Limit application during dormancy and follow package guidelines to avoid over-fertilization. Use granular, slow-release formulas, adjusting amounts for plant maturity. Water milk thistle after fertilization and wear gloves for protection.

Pruning: Milk thistle features spiny leaves and purple flowers. Prune in early to late spring, removing dead foliage to promote healthy growth. This maintains shape, improves air circulation, and minimizes pests. Use clean, sharp tools for effective pruning, encouraging vigorous regrowth.

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