Sow thistles – Edible, coffee extender, sacrificial plant Posted in: Columns Backyard Horticulture There are several plants in the Sonchus genus that have become naturalized all over the world. Sonchus oleraceus, common sow thistle, is similar to other Sonchus and it’s difficult to tell the difference. The ones most similar, S. asper and S. arvensis, are also called sow thistle and can ...PLEASE LOG IN FOR PREMIUM CONTENT. Our website requires visitors to log in to view the best local news. Not yet a subscriber? Subscribe today!