Familiar to gardeners and laymen across the globe, Milk Thistle was once native to southern Europe, but is now widely distributed around the world. The good news is that it grows anywhere, the bad news is that some consider it nothing more than a weed. Known by many names, including Saint Mary's Thistle and Scotch Thistle, it produces a lovely purple bloom in the spring and summer and is commonly used in teas and medicinal remedies.