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Plants of the Eloise Butler Wildflower Garden

The oldest public wildflower garden in the United States

Eastern Bluestar

Common Name
Eastern Bluestar (Bluestar, Willow Amsonia)

 

Scientific Name
Amsonia tabernaemontana Walter

 

Plant Family
Dogbane (Apocynaceae)

Garden Location
Upland

 

Prime Season
Late Spring Flowering

 

 

Eastern Bluestar is a perennial, erect, clump forming plant grows from 1 to 2-1/2 feet high with leafy light green smooth stems that are slightly angled.

The leaves are alternate, bright green, up to 6 inches long and 2-1/2 inches wide with smooth margins, a single main mid-rib vein, and a slender stalk - like willow leaves. The upper surface is smooth, but the underside may have fine hair, especially when young.

The inflorescence is a loose cyme of individually stalked flowers atop the stem.

The individual flower has a tube shaped corolla with five spreading lobes. Each lobe is narrow and the effect is star-like when the flower opens and the lobes spread outward horizontally. At the base of each lobe is a paler patch of color - either white or yellow, above which are numerous stamens. The corolla can be whitish early on if there is too much shade, otherwise it is a very nice pale blue. The exterior corolla of the flower is a deeper shade of blue than the interior - quite striking. The throat of the corolla has a band of fine hair. The green calyx has 5 triangular teeth. Each flower spans about 3/4 to 1 inch.

Seed: Mature flowers produce a cylindrical follicle that splits along the side to release its seeds.

 

Habitat: Eastern Bluestar will grow in average well drained soils in full sun to partial shade. The more shade, the lighter the color of the corollas, plus, the plants will become floppy. There are a number of cultivars available in the nursery trade.

Names: The genus Amsonia, is an honorary used for blue-flowered herbaceous perennials and named for 18th century Virginia physician Dr. Charles Amson. The species, tabernaemontana, is another honorary, named for Jakob Theodor von Bergzabern (d. 1590), who Latinized his name to Tabernaemontana. He was the personal physician of the Count of the Palatine, Heidelberg, Germany and published a herbal titled Neuw Kreuterbuch in 1588-91. The author name for the plant classification, 'Walter', is Thomas Walter (c1740 - 1789) a botanist known for his book Flora Caroliniana (1788) an early catalog of the flowering plants of South Carolina where this particular species grows. The alternate common name of Willow Amsonia refers to the plant's willow-like leaves.

See bottom of page for notes on the Garden's planting history, distribution in Minnesota and North America, lore and other references.

plant drawing

Above: Eastern Bluestar forms a nice clump in sunny to partially shady locations. Drawing ©USDA-NRCS Wetland Flora Guide.

Below: Once the flower opens, the color is a pale blue, much paler than the outside of the corolla (1st photo) prior to unfolding.

Eastern Bluestar flower buds Eastern Bluestar flower

Below: 1st photo - The corolla tube has a fringe of fine hair at the throat. Note also the small triangular teeth on the green calyx. 2nd photo - Flowers in too much shade will be whitish. Note in both photos the small yellow patch at the base of the corolla lobes.

Eastern Bluestar calyx Eastern Bluestar white flower

Below: The leaves are bright shiny green on the upper surface and have the shape of willow leaves, hence the alternate common name.

Eastern Bluestar Eastern Bluestar stem Eastern Bluestar leaf
Eastern Bluestar

Notes:

Notes: Eastern Bluestar is not native to Minnesota. It arrived in the Garden prior to 1986. It is native in the US from Kansas south to Texas and then eastward to the coast, reaching as far north as Illinois, Indiana, Ohio, PA and NY. It does grow well here.

References and site links

References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.

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