Sonchus oleraceus

Common Sowthistle Identification & Control

Common Sowthistle, also widely known as Annual Sowthistle, Hare's Lettuce, or Milky Tassel, is an exceptionally aggressive, fast-growing summer annual broadleaf weed in the aster family. Native to Europe and Asia, it has successfully colonized gardens, crop fields, and lawns globally. It features hollow, upright stems that bleed a thick white sticky sap when cut, deeply lobed dandelion-like leaves, and clusters of small, pale-yellow flower heads that mature into fluffy white wind-dispersed seedheads.

Sunlight Full Sun to Partial Shade

Watering Tolerance Moderate

Soil Adaptability Any Soil / Loam / Wet Clay

Growth Temp 8°C - 35°C

Danger / Toxicity Pet Safe / Milky Sticky Latex

Botanical macro photography of Common Sowthistle (Sonchus oleraceus) - Plant AI care and control database

How to Identify Common Sowthistle

An upright annual with hollow stems bleeding milky white sap, deeply lobed opposite leaves clasping the stem, and clusters of yellow flowers.

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Milky White Sap: Hollow green-purple stems are succulent and immediately bleed a thick, sticky, bitter white latex when cut or bruised.
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Clasping Lobed Leaves: Soft, blue-green leaves are deeply lobed with pointed tips, showing pointed 'ears' (auricles) that clasp tightly around the stem.
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Fluffy White Seedballs: Pale-yellow flower heads bloom in clusters, maturing into round, fluffy white seedballs resembling small dandelions.

💡 Plant AI Tip: Common Sowthistle is easily confused with Dandelion! However, Dandelion has zero leaves on its flower stalk, while Sowthistle has highly branched flower stalks carrying multiple clasping leaves.

Complete Care & Management Guide

Access highly technical, scientific management directives to control or cultivate Common Sowthistle effectively.

Highly adapted to moist and dry soils. It grows vigorously in early spring moisture but survives dry spells by accelerating its seeding cycle, producing seeds and dying in summer.

Controlled effectively by mowing. Mowing cuts off the tall, upright seedheads before the heart-shaped pods open, preventing seed dispersal and disrupting its annual lifecycle.

Thrives in nutrient-poor and highly disturbed soils. Regular fertilization helps garden plants grow densely, shading out emerging sowthistle seedlings.

Prefers Full Sun to partial shade. It struggles under dense forest canopies and dense, thick lawn turf shading. Shading lawns suppresses it.

Thrives in newly tilled soils, gardens, crop fields, and roadsides. It easily grows in dry, compacted, or poor soils where other plants struggle.

Reproduces strictly by seeds. A single plant can produce up to 100,000 seeds that can remain viable in the soil for over 50 years.

A summer annual. Germinates in spring, grows rapidly to flower in late summer, and is completely killed by the first winter frost, leaving seeds behind.

Features an exceptionally deep, thick vertical taproot anchored to a massive woody root crown. Complete manual extraction requires a sturdy spade.

Occasionally targeted by sowthistle seed beetles, which feed heavily on the seed heads, acting as a helpful natural biological control.

Highly disease-resistant. It suffers virtually zero structural damage from natural plant diseases, maintaining highly aggressive growth.

To control Common Sowthistle organically, manually dig up young rosettes in early summer before they develop their tough, woody taproot and bristly seed spikes, and mulch heavily.

Common Diseases & Treatment

Milky Latex Staining

Symptoms: Symptoms: Cutting the hollow stems bleeds a sticky white sap, causing sticky dark stains on hands and pruning shears.

Action: Action: Wear gloves. Wash skin with warm soapy water to dissolve the latex. Wipe pruning shears immediately with alcohol.

Wind Seed Dispersal

Symptoms: Symptoms: Small yellow flowers mature into round, fluffy white seedballs, releasing seeds carried by autumn wind.

Action: Action: Hand-shear the yellow flower heads immediately before they can turn white and fluffy. Place seedheads in a sealed trash bag.

Frequently Asked Questions

How is Sowthistle different from Wild Lettuce?

Sowthistle (Sonchus oleraceus) has completely smooth, non-spiny leaf undersides, and leaf bases with pointed auricles that wrap around the stem. Wild Lettuce (Lactuca serriola) has a highly distinct, rigid row of sharp spines underneath the leaf central vein.

Why is it called 'Sowthistle'?

It is named 'Sowthistle' because historically, domestic female pigs (sows) were observed to feed exceptionally greedily on the succulent, milky-sap-filled leaves, and the plant was cultivated in parts of Europe as a nutritious livestock forage.

Are the leaves edible for humans?

Yes. Young, tender spring leaves are edible raw or cooked, tasting somewhat like bitter dandelion greens. They are widely harvested in Greece and New Zealand (known as Puha) as a highly nutritious green packed with vitamins.

What is the best way to get rid of it?

Because it has a shallow, weak taproot, it is very easy to pull out by hand, especially when the soil is wet. Hand-pull young rosettes in early summer before they develop their branched, hollow flower stalks.