Larry Hurley writes about one of his favorite blue flowering perennials. There are a number of blue-flowered, spring-blooming perennials. A group you should consider are in the genus Amsonia, commonly known as Bluestar. Several are native to the United States, and one, Amsonia tabernaemontana, is native to Maryland. This species gets two to three feet tall, and blooms for several weeks in late April through early to mid-May, depending on weather conditions. It has pale blue flowers and nice yellow fall color. It grows in full sun to partial shade.