HARDINESS: Zones 3 to 9
PREFERRED SOIL pH: Neutral
PREFERRED SOIL TYPE: Average, well-drained
PREFERRED LIGHT: Sun to partial shade
ATTRIBUTES: True-blue flowers in early summer, golden fall foliage; for beds
SEASON OF INTEREST: Early summer and fall
FAVORITES: A. abernaemonfana for Zones 3 to 6; A. hubrectii, Zones 6 to 9
QUIRKS: Needs good soil drainage, little or no fertilizer
GOOD NEIGHBORS: Fall asters, butter daisy, butterfly weed, coreopsis, rudbeckia
WHERE IT GROWS BEST: Sun, well-drained soil
POTENTIAL PROBLEMS: Pest and disease problems are rare
RENEWING PLANTS: Lives many years; divide in early spring
CRITTER RESISTANCE: Good
SOURCE: Division, seeds
DIMENSIONS: 2-4 ft (0 6-1.2 m) high, 2-4 ft (0.6-1.2 m) wide
Bluestar in the Landscape
Like other plants with blue flowers, bluestar is always welcome in the garden because of its ability to flatter everything in its presence. Hardy and dependable, bluestar is a cinch to grow. A wildflower that thrives in meadows and on roadsides, bluestar is accustomed to neglect in the field, making it a care-free natural for any low-maintenance garden.
Bluestar's airy flower clusters are composed of dozens of tiny porcelain-blue stars that appear from spring to well into summer. This is a perennial that looks shrubby because of its narrow leaves, woody stems, and stocky posture. To make the blue flowers stand out to best effect, put blues tar in the company of other early-summer favorites, such as yellow coreopsis or pastel-hued columbine and foxglove. You can also use bluestar to create a cooling patch of blue that works as a garden accent in front of shrubs or evergreens.
Many early-season bloomers fade away when fall rolls around, but not bluestar. The elegant foliage turns golden yellow, creating a lovely accent late in the year. This part of bluestar's life cycle gives you a little extra mellow color to combine with fall-blooming asters, crysanthemums. butterfly weed, or rudbeckias, all of which stand at approximately the same height as bluestar and benefit from the background color.
In Zones 3 to 6 the name bluestar goes to Amsonia tabernaemontana, also known as willow amsonia, for its willowlike leaves. In warmer climates that name is applied to another species. Sometimes called Arkansas bluestar, A. hubrectii is a taller, wispier plant with almost needlelike foliage. Like its hardier cousin, Arkansas bluestar is easy to grow in any sunny, well-drained spot. Hardy through Zone 6, Arkansas bluestar reaches 3-4 ft (1-1.2 m) at maturity.The profuse flowers in late spring are pale periwinkle to steel blue, and the dazzling fall foliage is a glowing gold.
This native wildflower luxuriates in moist but well-drained soil, but it can endure dry conditions later in the summer when drought is most likely to hit and the flowering period is behind it. Don't bother to lavish this tough perennial with rich compost or copious fertilizer, because too many nutrients can lead to soft, floppy growth and fewer flowers. Full sun is best in cool-summer climates, but partial or afternoon shade is preferred where summers are hot and dry.
If the plants become leggy in midsummer, trim them back by about one-third to enhance the appearance of the golden fall foliage. Pruned plants will rebound and fill out, although they won't flower again until the following year.
Bluestar is a modest spreader that is always willing to give up small divisions dug from the outer edges of the clump in early spring. When transplanting divisions, allow 2-3 ft (0.6—1 m) of space between new plants to allow enough room for them to spread as they mature.