Milk thistles can grow to be 30 to 200 cm (12 to 79 in) tall, and have an overall conical shape. The approximate maximum base diameter is 160 cm (63 in). The stem is grooved and more or less cottony. The largest specimens have hollow stems. The leaves are oblong to lanceolate. They are either lobate or pinnate, with spiny edges. They are hairless, shiny green, with milk-white veins. The flower heads are 4 to 12 cm long and wide, of red-purple colour. They flower from June to August in the North or December to February in the Southern Hemisphere (summer through autumn). Learn more about Blessed Milk-Thistle