Stunning, super-sized, white flowers reach up to 12" across! The flowers open green, mature to white, and then age back to green. The flowers appear on new wood of the current seasons growth so it is best to do any pruning in late winter. Full size flower heads typically appear on plants that are at least three years old, once plants have had ample time to establish strong root systems. The soil pH won't affect bloom color. Plants grow best in full sun and well-rained soil.