This North American perennial from the tall-grass Prairies looks fantistic in a naturalistic planting design. Its light-green foliage looks a bit like a yucca leaf, but it only grows to around 60cm tall. In Summer, a long, branched flower spike emerges above the clump and is topped by tiny, stemless, greenish-white flowers tightly packed into round thistle-like blooms. The flowering lasts for ages and looks great even when the flowers have long since finished.