Plant Profiles Sow Thistle Sonchus Arvensis

Often mistaken for a common dandelion, sonchus arvensis is a medicinal plant known by many names. Field snow thistle, milk thistle, tree sow thistle, swine thistle, gutweed, dindle and corn snow thistle are all one single plant. Truthfully, in appearance snow thistle does resemble a dandelion and have very similar medicinal properties but the differences can be spotted.  A snow thistle will have a firmer but possibly thinner stem than and dandelion and can also have multiple blooms on one stem while dandelion generally do not.

These tall, erect plants can reach 1.5 meters or nearly five feet tall. They’re hollow and contain a milky sap. The ray flowers of this thistle resemble the sun and can reach 5 cm in diameter. When the ‘fruiting head’ appears, the flower goes from a yellow sunburst to a snowball looking puff of seeds that can be carried by wind, animals or humans to spread the flower.

Usually flowering June through October, these flowers thrive in everyday places such as waste ground, roadsides and railroads. These places being so common they’re relatively easy to spot. They’re native to Eurasia and are a very aggressive species. Intentional spreading of the plant is frowned upon for that reason. Even now the plant is becoming more widespread as time goes on.

There are two subspecies of sonchus arvensis discovered as of yet. Glabrescencs (Geunth.) Grab. & Wimm ( Also known as Variety uliginosus (Bieb.) Nyman) and arvensis are the two known variations of sonchus arvensis.

Although beginning in Europe and western Asia areas, today snow thistle can be spotted in all countries of the USA except Nebraska, Kansas, Virginia, West Virginia, North Carolina and Alaska. The first spotting of the plant was in North America was in Pennsylvania in 1814, most likely transported by seed contamination. While not confirmed, since it does grow in Texas and New Mexico, it’s a safe bet that it also grows in Mexico. It is also present in some parts of Canada.

In addition to its medicinal uses, snow thistle is also able to be used as a livestock feed. Sheep and cows will gladly eat the plant and it’s been known to be used for rabbit forage as well. The nutrition of sonchus arvensis is similar to alfalfa but the texture and taste of the plant is enough of a difference for animals and may not be as widely accepted.