In our acidic soil, 'Blue Billow' is a wonderful blue lacecap with large, flat flower-heads. The buds start out a rich royal blue, opening to masses of nice light blue flowers that are held in open plates, horizontal and facing the sky. The plant is a vigorous grower and a profuse bloomer. The foliage is very serrated, and a nice rich green with some bronzing in the full sun. The plant in the photo is in our garden, and is 5 years old. Grown in medium shade, the plant will be more open growing. In more sun, it will be shorter and much more compact.