Plant rhizomes 12 to 24 inches apart. Close planting results in immediate effect, faster clump formation, and more color but makes dividing clumps a necessity in two to three years. Plant each of the rhizome "toes" facing inward towards each other.
[Wonderful combination of plants. I think I'm looking at foxglove, tall bearded iris, and purple violas. Looks like maybe lamb's ear in the bottom left corner--excellent color foil.] What a great looking garden