Cardoons may look like the edible globe artichoke plants and the stalks are technically edible, but the main reason for growing cardoons is for their amazing looks. The large jagged, silvery-gray leaves can grow up to three feet long and are quite quite stunning in the summer garden. When the thistle-like flowers bloom in late summer, the whole effect is amazing, with plants growing up to six feet tall and two to three feet wide. Pollinators love the purple flowers that can be harvested and dried for flower arrangements. For the record, it's primarily the stalks of the cardoon that are considered edible, as the globe-shaped flowers are inferior in taste and size to the green globe artichoke. Cardoons are considered invasive in California, and overgrowths have been reported in Marion County, OR, and Clark County, WA.