Gardening Edible Gardening Herbs Milk Thistle By Viveka Neveln Viveka Neveln Instagram Viveka Neveln is the Garden Editor at BHG and a degreed horticulturist with broad gardening expertise earned over 3+ decades of practice and study. She has more than 20 years of experience writing and editing for both print and digital media. Learn about BHG's Editorial Process Updated on February 1, 2017 Share Tweet Pin Email This striking member of the daisy family has thorny, variegated foliage and purple blooms that resemble large thistles. Remove the blooms before seeds mature to prevent the plant from self-seeding and becoming weedy. When cut, the plant produces a white, milky liquid, which is how it got its name. The plant has been used for centuries as a treatment for diseases of the liver and gallbladder. In its native range, it is an annual, but it may overwinter in zones 5-9. Milk Thistle Overview Genus Name Silybum marianum Common Name Milk Thistle Plant Type Annual, Herb Light Part Sun, Sun Height 3 to 8 feet Width 2 to 3 feet Flower Color Blue, Purple Season Features Summer Bloom Special Features Cut Flowers, Low Maintenance Zones 10, 11, 3, 4, 5, 6, 7, 8, 9 Propagation Seed Was this page helpful? Thanks for your feedback! Tell us why! Other Submit