Blue Star (Amsonia tabernaemontana) is native to the central U.S. (USDA hardiness zones 3-9). This herbaceous perennial is frequently seen growing in open woodlands in the midwest and south to Florida and Texas.
In mid-spring (in Tennessee), plants are filled with clusters of soft light blue star-like flowers, each nearly ¾ inches across. This clump-forming perennial stands erect 2-3 feet tall and wide. Dull green willow-like leaves turn bright yellow in autumn although this is not an every year occurrence.
Blue star grows in any average, moderately moist, well-drained soil and in full to partial sun. It prefers moist, loamy soils, but it tolerates heavy clay soils. After its first year planted, it is summer dry tolerant. When grown in full sun, plants require no pruning or staking. When grown in some shade and/or in rich soils, however, blue star tends to become more open and floppy and often requires some staking or pruning. For a neater appearance, cut back stems by one-third to one-half after flowering to develop a dense mound plant form.
This easy-to-grow long-lived perennial requires very little extra maintenance. Blue star is not troubled by insect or disease problems. Occasionally, rust disease may become problematic in wet summers. Deer usually leave the foliage alone. Mass several plants together in rain gardens, in open woodland areas, and containers. Showy blooms may be used in cut arrangements.
‘Blue Ice’ is a selection from White Flower Farm with periwinkle blue flowers. Flowers are larger than the species. The bright green foliage forms 12-16 inches tall, compact spreading plant. Leaves turn an above average yellow color in fall.
‘Short Stack’ is another seedling selection from a batch of seedlings of the var. montana. It’s a dwarf version, barely half the size of species at 10 inches tall x 18 inches wide. Clean dark green foliage contrasts nicely with the medium sky-blue flowers atop the plant.