Bluestars are in the genus Amsonia. There are at least twenty-two known species, and most are native to the Eastern United States. All are in the Apocynaceae (Dogbane) family, so named because the milky sap is slightly toxic to dogs. Due to the unpleasant taste of the sap, Bluestars are deer- and rabbit-resistant. There are no known serious insect or disease problems.
They grow in full sun to part shade in average, well-drained soils. For our hot South Carolina climate, it’s best to plant it in an area that gets some light afternoon shade during the afternoon. Remember, the plants will be floppy if planted in too much shade.
Two of my favorite species are the Eastern Bluestar (Amsonia tabernaemontana) and Threadleaf or Hubricht’s Bluestar (Amsonia hubrichtii). The genus Amsonia is named after Dr. Charles Amson, an 18th-century doctor and amateur botanist from Virginia. Both are excellent additions to a pollinator garden and attract a wide variety of butterflies and bees.
Eastern Bluestar (Amsonia tabernaemontana) is native to a large area of the United States and will grow in USDA planting zones 3 to 9. The plant is 2 to 3 feet tall and wide and has blue star-shaped flower clusters that bloom in April and May. The linear willow-shaped foliage will turn yellow in the fall. The species epithet, tabernaemontana, is named after the 16th-century German herbalist Theodorus Tabernaemotanus.
Threadleaf, also known as Hubricht’s Bluestar (Amsonia hubrichtii), was first discovered in 1942 by Leslie Hubricht in the Ouachita Mountains of central Arkansas and Oklahoma. It is hardy in USDA planting zones 5 to 8 and will reach a height and width of 2 to 3 feet. The powder-blue star-shaped flowers bloom from April to May. The feathery
Read more on hgic.clemson.edu