Arkansas blue star named perennial plant of 2011
by Jo Ellen Meyers Sharp
A North America native plant with three seasons of beauty is the 2011 Perennial Plant of the Year. Although native to Arkansas and Oklahoma, Arkansas blue star (Amsonia hubrichtii) is found throughout most of the United States. Named after Leslie Hubricht, a biologist who found the species growing wild in Arkansas in 1942, it's winter hardy in USDA Zones 4 through 9.
The American Horticultural Society rates amsonia as a good plant for heat zones 5 to 8. The West Coast's go-to gardening book, "Sunset," says it does well in zones 2 through 24.
Amsonia hubrichtii grows about 3 feet tall and wide, and is quite showy when grown in a mass of three or more plants. In late spring and early summer, clumps of blue, star-like, butterfly-attracting flowers top the stems of medium-green ferny foliage. The flowers form slender seed pods, which eventually fall to the ground. In fall, the foliage turns golden, which is every bit as showy as amsonia's spring blooms.
Plant amsonia in full sun, where it gets six hours of direct sun a day, or in part sun, with four hours of direct sun. In shadier locations or areas with rich soil, the plant will flop. In the hottest parts of the United States, grow amsonia where it's protected from afternoon sun.
The shrub-like, clump-growing perennial prefers average, well-drained, evenly moist soil, but is quite tolerant of drier soil, especially after it's established. Amsonia is easy to propagate by division in early spring.
This is a very versatile plant. The cool-blue flowers help tone down or complement the colors of companion plants. The fine, green billowy foliage provides unusual texture, softening the bolder leaves of nearby perennials. Because of its gorgeous late-season color, consider pairing amsonia with other plants that bloom or have good leaf color in fall, including ornamental grasses, asters (Symphyotrichum), monk's hood (Aconitum), sedum (Sedum or Hylotelephium spectabile), Viburnum, smoke tree (Cotinus), Virginia sweetspire (Itea), dark-leafed elderberry (Sambucus) and oakleaf hydrangea (H. quercifolia). Or, plant with perennials that have attractive seed heads in fall, such as coneflowers (Echinacea) and black-eyed Susans (Rudbeckia).
Amsonia takes about three years to reach its mature size. It's very low maintenance and doesn't seem to be bothered much by insects or diseases. For a fuller plant in fall, cut amsonia back to about 8 inches tall after it blooms, if desired. In early winter, cut the plant to the ground when it starts to look bad.
A member of the willow family, amsonia has a milky sap that may be irritating to sensitive skin, so some gardeners might want to wear gloves when working with the plants. The sap must give the plant a bad taste because deer don't seem to bother it.
Sometimes known as the Hoosier Gardener, Jo Ellen Meyers Sharp lives in Indianapolis, where she manages perennials and woody plants for a large, independent garden center. A freelance writer, her work appears in many publications, including The American Gardener and Garden Gate. Sharp also speaks about gardening throughout the Midwest and is a director of the Garden Writers Association.