Twist-N-Shout is the lacecap in the Endless Summer® line, with a ring of showy florets around a center of small fertile flowers rather than a solid ball. Hydrangea macrophylla 'PIIHM-I' grows 4 to 5 feet tall and wide in part sun to part shade, hardy from Zone 4 through Zone 8, and reaches full size in three or four seasons.
Like the rest of the line it flowers on both old and new wood, so a hard winter that kills last year's buds does not cost you the season. Bloom starts in early summer and continues into fall, with fresh heads opening as older ones fade.
The stems are deep red, which shows against the flowers, and the foliage takes on burgundy tones in fall. Bees come to the fertile center through the bloom.
The color of the blooms depends on your soil. Acidic soil, roughly pH 5.5 and below, gives blue with a deeper blue eye at the center. Neutral to alkaline soil gives pink. Aluminum sulfate in spring pushes toward blue, and soil sulfur works more slowly but holds longer.
Give it morning sun with afternoon shade, consistent moisture, and shelter from cold wind. Avoid hard spring pruning, since that removes the old wood buds and costs you the early flush. The leaves wilt on hot afternoons and recover by evening, so check the soil before watering again.