Learn about the Arkansas bluestar

Arkansas bluestar

Amsonia hubrichtii

By Ethan Johnson, Plant Records Curator

Arkansas bluestar is a beautiful foliage plant whose native habitat is well-drained creek banks, fields, and rocky outcrops. The leaves are very narrow, adorning the plants in wonderful, feathery bright green attire. In the landscape it has a softening effect especially when used en masse in borders, along walkways and by stonework. The bright yellow to golden fall foliage can last for a few weeks, typically peaking in October at Holden Arboretum, but starting as late as November at Cleveland Botanical Garden.

Arkansas bluestar is not susceptible to browsers, insects or disease. This tidy perennial can be relied upon to remain in its place in your garden although I have welcomed and transplanted seedlings at home in Willoughby. All it requires is a sunny location and reasonably good soil drainage. When grown in rich soil or in too much shade, plants become open and floppy. Routine maintenance for properly sited plants includes cutting back stems to the woody base in late fall. After flowering, shearing 4-6 inches off the top, cutting the outer stems more to round off a plant’s form keeps it from becoming too open or relaxed in formal garden settings.

Flowers appear rather sparsely on young plants, increasing in profusion with age. Bloom at Holden Arboretum usually starts by the second to third week of May and lasts into the first or second week of June. The pale blue, ½ inch, star-like flowers are borne in loose terminal panicles up to 5 inches long and 3 inches wide. Butterflies, hummingbird moths, bumblebees and carpenter bees serve as pollinators.

Native to the Ouachita Mountains of central Arkansas and southeastern Oklahoma, this species was named in honor of Leslie Hubricht who discovered it in 1942. In Northeast Ohio gardens, it was very uncommon until the past quarter century. The plant has no serious insect or disease problems. A word of warning, some people are highly sensitive to the milky sap produced by all species of bluestar, which can cause itching or burning upon contact. Perhaps this is a reason why groundhogs, rabbits and deer tend not to browse the bluestars! Arkansas amsonia generally prefers evenly moist soil but tolerates some dry and relatively short wet spells. Full sun is best. Transplanting of established plants can be performed in late spring, in early spring before growth starts, or in fall. Potted plants are best planted from early spring to late summer so they can be rooted in before winter and not “heaved” out of the ground by frost.

Arkansas bluestar may be found at the Arboretum south of the Corning Visitor Center in the bed adjacent to the small amphitheater, in the Layer Rhododendron Garden west of Sherwin Pond, and at the Botanical Garden in the circle bed in the Campsey-Stauffer Gateway Entry Garden, in the C.K. Patrick Perennial Border, and northeast of the library near East Boulevard.

LIGHT: Full sun to part shade SOIL TYPE: Moist, well-drained acid to neutral soil pH MATURE SIZE: 3 to 4 feet tall and wide

BEST LOCATION: USDA Zones 4 to 9

SOURCE: Local garden centers HOW TO: Be sure to check for narrow leaves between 1/16th and 1/8th of an inch in width as nurseries may also offer hybrids with other bluestars that have wider leaves.

MEET THE STAFF

Ethan Johnson is the Plant Records Curator.He learned to keep records while working for the Arnold Arboretum (1985-89) and Holden Arboretum (1981-82, 1989-present) while volunteering for the International Dendrological Research Institute, Ohio Nursery and Landscape Association Plant Selection Committee and the American Conifer Society. He was the point person when the American Association of Museums accredited Holden Arboretum as the sixth public garden in the U.S. as a museum, has labeled and inventoried Holden Arboretum’s plant collection and has been keeping plant records at Cleveland Botanical Garden since 2015.