Vol. 20 Issue 3, Fall 2015
By Julie Borneman, Watermark Woods
Photo by William S. Justice, hosted by the USDA-NRCS PLANTS Database
If you have not tried Amsonia tabernaemontana in your garden, it is time you gave it a chance. Commonly called bluestar or blue dogbane, this Piedmont native is sure to please. It has multiple seasons of interest, does well in any soil and is even deer and rabbit resistant.
Amsonia puts on a nice spring show with clusters of star-like blue flowers from April to May. However, most people do not choose this plant for the flowers, but rather for the fall foliage. The foliage stays neat and tidy throughout the growing season then turns an appealing bronze in the fall. A real show stopper and the perfect backdrop for purple fall asters or a spooky jack-o-lantern.
In the wild, Amsonia tabernaemontana can be found along riverbanks and woodland edges. This is a carefree easy to grow perennial that prefers moist yet well-drained soils, but knows how to handle a dry Virginia summer. Bluestar does best in full sun, but will do just fine in partial shade. However, when grown in partial shade it can become leggy and require staking.
Amsonia is a clump-forming herbaceous perennial. This means that it dies back to the ground every winter. It has multiple stems and can grow up to 4 feet tall. If you prefer a shorter bushier plant, you can cut it back by pruning 1/2 to 1/3 of the plant after flowers finish up in the spring. This will cause the foliage mound to be more compact and rounded for a tidier look in the fall. Cutting the plant back after flowering can eliminate the need for staking shade grown plants.
As with most native perennials, bluestar has relatively few disease or pest problems. It is in the dogbane family and has milky sap, thus is distasteful to deer and rabbits. That in itself makes this plant a real winner for some gardeners. Amsonia is a great benefit to pollinators. The flowers attract the Ruby-throated Hummingbird and many insects, including the Large Carpenter Bee (Xylocopa virginica), Hummingbird Moths (Hemaris spp.), and numerous butterflies.
There are several varieties of Amsonia available at local garden centers. The two most widely cultivated are tabernaemontana, a true Piedmont native and hubrichtii, a more southern native. Hubrichtii has threadlike leaf, similar flowers and thrives in a similar habitat. The feathery foliage of Amsonia hubrichtii is significantly different from the broad leaves of Amsonia tabernaemontana and offers a very different look to the plant. While not truly native to Loudoun County, it does just fine here but does tend to seed itself around a bit.
With both aesthetic interest and pollinator benefits, Amsonia is a must for any gardener.
Resources:
www.chicagobotanic.org/downloads/planteval_notes/no18_amsonia.pdf
www.wildflower.org/plants/result.php?id_plant=AMTA2
missouribotanicalgarden.org/PlantFinder/
mtcubacenter.org/plants/blue-dogbane/
www.plants.usda.gov/core/profile?symbol=AMTA2
www.illinoiswildflowers.info/woodland/plants/bluestar.htm