Threadleaf bluestar is grown for two seasons at once: a haze of soft, powder-blue stars in late spring, and a billow of fine, needle-thin foliage that turns a blazing clear gold in fall. Native to the Ouachita Mountains of central Arkansas, Amsonia hubrichtii forms a large, dense, shrub-like clump of upright stems clothed in those threadlike leaves, and the autumn color alone earns a place in any sunny border.
Most bluestars are smooth, cool customers; Amsonia ludoviciana is the outlier of the group. The Louisiana bluestar belongs to the dogbane family, Apocynaceae, and shares the clan's five-petaled, star-shaped flowers and milky sap, but the leaves set the species apart: narrow and willowy, and unusually clothed beneath with a grey-white felt, a woolly tomentum that catches the light and lends the whole plant a soft, silvered cast rare in the genus. In spring, clustered flowers of a clean sky-blue open at the tips of the upright stems, quiet and steely and worked over by the first butterflies of the season.
Dwarf bluestar is the compact, well-behaved member of the clan, a tidy mound of upright stems and soft green leaves topped in late spring with clusters of powder-blue, star-shaped flowers. Often treated as a low form of the eastern bluestar, Amsonia montana stays small and shapely, a fine choice where the taller bluestars would sprawl.
Eastern bluestar is the bluestar most gardeners know, a robust native perennial with broader, willowy oval leaves and the clear blue, star-shaped flowers that name the genus, carried in clusters at the stem tips in spring. Amsonia tabernaemontana grows happily in deep, moist soil in part shade, and rewards almost any reasonable site with bloom and easy good health.
