Cardoon makes a dramatic evergreen statement in the sunny perennial border with its 3-4' long, arching, ghost-like, jagged soft-grey foliage. Once the 3' wide clumps are established, they are topped with 6' tall stalks of blue-violet, thistle-like flowers in late summer. After flowering, the plants die back to the ground for a month-long rest, then begin growing again. For a striking bold-textured accent plant in the garden, you aren't going to beat cardoon! Well-drained soils are best. Cardoon, which sounds more like a mythical place in Scotland than a plant, was actually chosen by the Royal Horticultural Society as one of the top plants of the last 200 years.