The annual sow thistle (Latin name: Sonchus oleraceus Family: Compositae) is often considered a common weed, avoiding acid soils and shady positions. You can often find it alongside roads in particular in autumn after the rain has started to set in. This plant has medicinal uses to it with qualities similar to dandelion and succory.
Some sources report that this sow thistle has 1500mg of calcium per 100g and 45mg of iron. It’s also high in potassium, phosphorus, magnesium and a good source of vitamin C. Not to mention the phytochemicals the flavones, stilbenes, polyphenols and glycosides that exhibit anti-inflammatory, anti-tumour and all round good stuff properties.
This thistle is distinctive from other thistles by the fact that it is without the spines of its relatives. It is hollow stemmed, with a milky substance exuded when the stem is broken. It has small, dandelion-like flowers, and soft, green, irregularly toothed leaves.
Note: there are 2 kinds of sow thistle: The annual (Sonchus oleraceus L.) with more prickly leaves and the perennial (Sonchus Asper L.) with "softer" leave edges. Use the one with the softer leaves for your horses. It is adored by livestock in general.
Because the Sow Thistle is nutrient-rich, it is a vegetable traditionally enjoyed by some Aboriginal and Maori groups in Australia and New Zealand, with historical records from the 1880s describing the gusto with which Aboriginal groups would harvest thistles from farmland. The milky sap has been used as a chewing gum by the Maoris of New Zealand.
Native Americans had many uses for this plant. A New Zealender by the name of Mawalagedera (2009) wrote a thesis about the antioxidant value of this plant, and makes a point that the a particular New Zealand Maori population has less incidence of colorectal cancer despite being in a very high risk group for the disease. She writes that sow thistle is a staple in the diet along with sweet potatoes, silverbeet (a close relative to spinach) and watercress. Perhaps these foods are offering the protective factor? She also writes the more mature plants have a higher antioxidant value.
A 2013 study reports sow thistle is may be an effective option for treating Diabetes because the high antioxidant value protects the liver, kidneys and blood plasma from damage caused by high blood sugar.
Horses love the annual plant so why not offer it as a treat?