Sonchus oleraceus, Sow thistle, Milk Thistle, Smooth Saw-thistle, Sow Thistle

Sonchus oleraceus, with many common names including Common Sow thistle, Milk Thistle, Smooth Saw-thistle, Sow Thistle, Annual Sow thistle, annual milk thistle, hare’s-lettuce, common milk thistle, colewort, field sow thistle, hare’s thistle, small sow thistle, Hare’s Colewort, Common Milk Sow-thistle, Milky Tassel, Milk-weed, Thalaak or swinies, is a plant in the dandelion tribe within the Asteraceae ⁄ Compositae (Aster family). The plant is native to Asia and Europe, and it can be found growing in North America, South America, Australia, and the Middle East. It is also found in Australia, Brazil, Canada, Falkland Islands, French Southern Territories, Greenland, New Zealand, Puerto Rico, Saint Helena, Saint Pierre and Miquelon, United States, Virgin Islands.

The name of the genus, Sonchus, is derived from the Greek word for hollow, and bears allusion to the hollow nature of the succulent stems, while oleraceus refers to its good taste. The Sow Thistles are sometimes mistakenly called Milk Thistles from the milky juice they contain; the true Milk Thistle is, however, a very different plant. Apart from that the common name sow thistle refers to its attractiveness to swine, and the similarity of the leaf to younger thistle plants. The common name hare’s thistle refers to its purported beneficial effects on hare and rabbits. It is a nutritious plant that contains several minerals (calcium, magnesium, iron, phosphorus, sodium, potassium and zinc) and vitamins (A, B1, B2, B3, B6, & C). The leaves are also great to use as an antioxidant.

Plant description

Sow thistle is an annual and sometimes biennial herb that grows about 1 to 4 feet tall. The plant is found growing in fields, orchards, roadsides, gardens, waste areas, forests, grassland, riparian habitats, freshwater wetlands, coastal estuaries, dunes, pastures, open disturbed areas in cultivated land, near waterways, burned areas, construction sites, rail yards, edges of yards, vacant lots and areas adjacent to buildings. The plant mostly grows on humus-rich, chalky, mild soils well-supplied with nutrients. The plant has deep tap root system which is upright with many branches. Stem is erect, 5 angled, that are 60 – 150 cm high, smooth and hairless on the lower part but glandular-hairy towards the top and on branches, hollow, thick, branched stems full of milky juice. They are dark green in color (sometimes tinted with a reddish-purple tinge).

Leaves

Leaves are lanceolate to oblanceolate in shape, hairless and dark green in color with pale white to purple veins. The first leaves are round with a slightly toothed margin with a few spines. They have sparse hairs on the upper leaf surface. The mature leaves are thin, soft and dark-green in color with irregularly-toothed margins ending in small, soft spines. The upper leaves are smaller than the lower leaves, stalk less and clasp the stems with claw like basal lobes. Leaves are thin and soft, measuring up to 36 cm long and 12 cm wide.

Flowers

Flower heads are yellow and are 5-6 mm in diameter and are borne on stalks at the ends of branches, in an irregular terminal panicle (a compound inflorescence with a main axis and lateral branches which are further branched, and in which each axis ends in a flower or bud), with or without hairs. Flowers tend to open primarily between the hours of 6 am till 11 am. The floral bracts at the base of the flower head are dull green, hairless and overlap each other in a vertical series. Flowering normally takes place from June to August.

Fruits

Fertile flowers are followed by achene (a dry indehiscent, non-opening, 1-seeded fruit) that is 2.5-4 mm long and 1mm wide, brown, 3-ribbed on each face, wrinkled with narrow margins and compressed and obovoid in shape. The seeds are light with white parachutes of silky hairs (pappus), the silky hairs being 5-8 mm long.

History

The species of this genus has been probably been consumed since ancient times. Dioscorides in the first century, mentioned two kinds of sónkhos, one more rough and prickly, the other more tender and edible (Laguna 1555), probably Sonchus asper and S. oleraceus (Osbaldeston 2000).

Traditional used and benefits of Sow thistle

• The plant is emmenagogue and hepatic.
• An infusion has been used to bring on tardy menstruation and to treat diarrhea.
• Latex in the sap is used in the treatment of warts.
• It is also said to have anticancer activity.
• Stem juice is a powerful hydragogue and cathartic, it should be used with great caution since it can cause colic and tenesmus.
• Gum has been used as a cure for the opium habit.
• Leaves are applied as a poultice to inflammatory swellings.
• An infusion of the leaves and roots is febrifuge and tonic.
• It is also used to treat a wide variety of infections.
• It is used in the treatment of headaches, general pain, diarrhea, menstrual problems, fever, hepatitis, salmonella infection, wars, eye problems, liver infections, infections, inflammation, and rheumatism.
• Juice of the plant is used for cleaning and healing ulcers.
• An infusion has been used to bring on a tardy menstruation and to treat diarrhea.
• Its leaves are considered refreshing and depurative, and they were directly consumed or prepared in infusion as a liver protector, or against pyrosis.
• Decoction of the whole plant is used against hemorrhoids.
• Other medicinal uses are mainly related to intestinal and skin disorders.
• Gum has been used as a cure for the opium habit.
• Leaves are said to clear infections and are diuretic, hepatic, sedative, and stomachic.
• They are also used in the treatment of eye problems, gastritis, salmonella infection, kwashiorkor and anemia.
• Use of leaf sap to treat earache and deafness is probably effective in cases where excessive amounts of earwax are the underlying cause of the problem.
• Roots are abortifacient, purgative and vermifuge.
• Juice expressed and tanked-up for hemorrhage during childbirth.
• An ointment made from decoction is applied for healing wounds and ulcers.

Culinary uses

• Young leaves are consumed raw or cooked.
• They usually have a mild agreeable flavor, especially in the spring.
• They can be added to salads, cooked like spinach, or used in soups, casseroles, etc.
• Stems can be cooked like asparagus or rhubarb.
• Young root can be consumed by cooking.
• Milky sap has been used as a chewing gum by the Maoris of New Zealand.
• This species has been commonly used as a wild green throughout the Mediterranean region, as recorded in Portugal, Spain, Italy, Slovenia, Croatia, Bosnia-Herzegovina, Greece, Cyprus, Turkey, Jordan, Egypt, Tunisia and Morocco.
• Its young leaves and stems are consumed raw in salads and cooked, both in soups, with legumes, fried with eggs or in omelets used as pastry stuffing, boiled and prepared as a salad, or boiled and then fried with olive oil, garlic, and other ingredients.
• This species is commonly prepared in mixtures with other wild species, as recorded in different Mediterranean recipes. Some examples are the Italian misticanza, a salad with a mix of several raw vegetables, the foie and the chòrta vramena, mixtures of several wild herbs previously boiled, the pasta sets de bosses and the minxes, in eastern Spain, traditional vegetable pies of wild herbs, or the Moroccan beqoul, a mixture of up to 20 wild food plants used to prepare a springtime meatless dish.
• Although it is generally collected for domestic consumption, it can also be found in some wild vegetable mixes sold in the markets of southern Croatia.
• Its flowers have also been used to curdle milk, as reported in some Italian regions.

Buttered Sow Thistle

Ingredients

• 1 or 2 handfuls sow-thistle leaves – young
• Butter or oil
• Beef stock or water
• Ground nutmeg – pinch
• 1 tsp. flour
• Salt and pepper

Direction

1. Heat some butter or oil in a pan and add the leaves.
2. Stir thoroughly to coat the leaves.
3. Add a good slug of stock or water, reduce the heat to a simmer, and cover.
4. Cook for about 5 to 10 minutes.
5. Add a pinch of nutmeg, the flour and some seasoning.
6. Stir everything, then add another knob of butter and melt into the sow-thistle over low heat.

Stir-fried Sow thistle & Pork

Ingredients

• ½-1 cup pork meat – shredded/sliced
• Light soy sauce
• Corn flour – pinch
• Water
• White wine or dry sherry
• Sugar – pinch
• Salt and pepper
• Sows thistles

Directions

1. Begin by slicing the meat into pieces about 2 inches long and 1/10th inch thick.
2. Set aside. Next, make up a marinade from the remainder of the first group of ingredients, using a splash of soy sauce, slugs of water and wine, seasoning and pinches of corn flour and sugar.
3. Mix together well in a bowl and then add the sliced meat.
4. Stir thoroughly so that all the pieces are coated and leave for 30 minutes.
5. Heat some oil in a frying pan and fry the ginger for a couple of minutes, stirring to prevent burning, then add the spring onion.
6. Stir for a minute, and then add the meat.
7. Stir-fry until the meat begins to cook.
8. Add the sow-thistle leaves and continue frying for another 3 or 4 minutes, stirring to prevent burning and distribute the heat.

Sow thistle with red onion, goat cheese and pine nuts

Ingredients

• 1/2 Bag packed with Sow thistle leaves
• 1 Clove of garlic, minced
• 1/4 Red onion, thinly sliced (or more if you like)
• Goat cheese, crumbled
• Pine nuts
• Olive oil
• 1/4 Cup chicken broth or more if necessary
• salt and pepper
• Nutmeg to taste

Directions

1. Rinse, chop and boil the Sow thistle leaves for a few minutes and Drain.
2. Heat olive oil in a big fry pan and saute the red onion for three minutes.
3. Add minced garlic and saute for another minute.
4. Lower the heat to medium and add the Sow thistle leaves while stirring.
5. They will shrink so you can keep adding leaves.
6. When they’re all shrunk, add some chicken broth and cover, simmer for ten minutes.
7. Season with salt, pepper and nutmeg.
8. Stir in a couple of table spoons of crumbled goat cheese, or to taste, and pine nuts.

Other facts

• It has also been used as animal fodder, especially for rabbits, pigs, and hens, as recorded in Spain and Portugal.
• The plant is a good companion for onions, tomatoes, corn as well as the cucumber and squash family.
• 4,000-5,000 seeds are produced in one single plant.

Prevention and Control

Prevention

Eradication of Sow thistle plants from ruderal spots close to farm crops before flowering will prevent the achene spreading by means of wind. Cultivated plant seeds must be clean and of a good quality and seeding must ensure optimum plant density. Crop rotations must be complied with, as well as suitable timing for summer and autumn ploughing. Hoeing must be carried out as often as needed, so that sow-thistle plants do not reach the flowering stage.

Physical/Mechanical Control

Young plants are easy to pull out and the tap roots will come with them, but as the plants get older and more firmly rooted, they cannot be pulled out without breaking off the stems, which will then regrow.

Plants which are cut off above soil level recover quickly. Hutchinson et al. (1984) recommended repeated autumn tillage in milder Canadian climates, or in spring after spring emergence of seedlings. Plants do not regrow from root fragments. However, deep burial of the seeds prolongs their survival.

Biological Control

CSIRO in Australia has been discovering the possibility of biological control of this weed and has so far recognized a rust fungus Miyagia pseudosphaeria, Aceria thalgi and the potential mycoherbicide pathogen, Aschochyta sonchi. The possibility of biological control had apparently been discovered earlier in Canada.

Chemical Control

Wide range of herbicides is being used to control Sow thistle either pre- or post-emergence in different crops. However the species has now developed resistance to ALS-inhibiting herbicides such as chlorsulfuron and metsulfuron-methyl in Australia. Widderick and Walker provide advice on appropriate herbicides for its control in wheat, how to manage the weed in Queensland and Northern New South Wales, and how to avoid further development and spread of herbicide resistance, including the dreadful prospect of glyphosate resistance.

Control by utilization

Cattle and sheep readily graze the plants, one of the reasons for its lack of persistence in pastures.

 

References

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