AMSONIA
Long ago, when I was studying perennial plants at the New York Botanical Garden, I was introduced to a statuesque plant that was holding court in one of the Garden’s perennial beds. It was nearly four feet tall, healthy and robust, as you might expect of a specimen living in such surroundings. Many elongated green leaves alternated up and down the tall stems, but at the time I thought they were nothing to write home about. The plant’s best feature was the profusion of pale blue, flat-topped flowerheads. Each flowerhead or corymb, as it is known botanically, was composed of a large number of five-petaled, star-shaped blossoms. The effect was lovely. Our instructor, an Englishwoman who never entered the classroom without a thermos of tea, told us the plant’s name: Amsonia tabernaemontana. We had to memorize it. Later I found out the common name, which is much more evocative: “blue star.” Though the flowers were impressive, I wasn’t so infatuated with the plant that I considered installing one in my home garden. I did, however, remember the Latin name for the test at the end of the course.
Later on, I met Amsonia tabernaemontana’s kissing cousin, Amsonia hubrichtii, sometimes known as Arkansas blue star. This amsonia, a little shorter at about 36 inches, had similar flowerheads and thin, thread-like leaves; but it had something else the tabernaemontana species did not have–autumn color. In the fall, the leaves turn a beautiful golden yellow shade. The plant is a clump-former, so in September, from even a short distance, a mature clump transforms itself into a magical golden haze. It is no surprise that Amsonia hubrichtii was named the Perennial Plant Association’s “Plant of the Year” for 2011.
The Perennial Plant Association is a trade group devoted, not surprisingly, to the promotion of perennial plants. Its annual “Plant of the Year” selections are not just worthy species, but mirrors of horticultural fashions. Amsonia hubrichtii is definitely a la mode. It is a North American native and hardy in USDA Zones 4 through 9, which makes it adaptable to most parts of the United States and Canada. Once established, it is drought tolerant and very easy to care for. Native plant lovers will appreciate its domestic provenance, prairie plant/ornamental grass aficionados will love its affinity with those kinds of plants and landscapers will be gratified that it provides more than one season of interest. Organic gardeners will rave about the fact that it is easy to grow organically. The only way that Amsonia hubrichtii could be more in step with the times would be if you could eat it.
Amsonia is a member of the Apocynaceae or dogbane family and its relations include vinca and asclepias, better known as milkweed. Dogbane family members are characterized by the milky sap that flows from cut stems. In the case of vinca and amsonia, blue or blue-purple flowers are also common. The genus Amsonia was named for an eighteenth century Virginian, Dr. Charles Amson. The species name, “hubrichtii” is in honor of Leslie Hubricht, who discovered it in the Ozarks in 1942. As I recall, Mr. Hubricht was a self-taught naturalist who made his name as a mollusk expert. Amsonia hubrichtii is a far cry from a mollusk, but some of the greatest discoveries have happened when scientists were looking for something else. I suspect that was the case with the Arkansas blue star.
There are a number of Amsonia species, cultivars and hybrids on the market, some of which share hubrichtii’s golden fall hues. If you have limited space or a container garden, you may want to try the hybrid Amsonia ‘Blue Ice,’ which grows only 12 to 15 inches tall. Its leaves are more like those of the tabernaemontana species than the hubrichtii, so the gold fall color may not appear as haze-like. There is also Amsonia ‘Short Stack,’ which reaches only about 10 inches tall. It does not have fall color, however.
Amsonia are frequently billed as “deer resistant,” though gardeners that I know with deer problems are always skeptical of that designation. Deer seem to have a deep and abiding awareness of plant fashions and are especially fond of anything that is either popular with humans or expensive for them to purchase. It seems reasonable that the milky sap harbored by amsonia and all dogbane family members may make the plants unpalatable in the same way that the milkweed sap absorbed by monarch butterfly larva make them unpalatable to predators. All you can do is try an amsonia in your garden and see what happens. Successful gardeners who live in areas with large deer populations are generally either good gamblers or great fence builders. They have my respect in either case.
For a good amsonia selection, try Plant Delights Nursery, 9241 Sauls Road, Raleigh, North Carolina, 27603, (919) 772-4794, www.plantdelights.com. If you want a printed catalog, they request that you either send ten first class stamps or one box of chocolates. Their highly entertaining website states that they prefer the chocolate