Trials conclude you can’t go wrong with Amsonia

I pay close attention to two plant evaluation programs. The first is at the Chicago Botanic Garden, where the growing conditions are very similar to Ozaukee County’s, and the second is the Mt. Cuba Center in Delaware, which specializes in trialing native plants.

Unlike plant trialing done by some companies, where plants are grown in ideal conditions, these two programs strive to test plants under realistic home garden conditions for a long period of time. Plants aren’t babied or fussed over, and what happens, happens.

When Mt. Cuba recently released the results of their trial of Amsonia, commonly known as bluestar, I was eager to beat the rush to find their favorite. When they named Wood’s sedge (Carex woodii) as the best Carex in their trials last year, any grower who had it immediately sold out and still can’t meet with the demand for the coming season.

So I was relieved and very surprised to find out that there was no standout in the Amsonia evaluation because almost every variety they trialed for 10 years was considered top-rated.

It turns out that, generally speaking, Amsonia are just great plants.

The results of the trial bear out much of what I’ve observed in my own garden: they are virtually pest and disease free and ask for no more care than watering the first year and cutting back dead stems in spring.

They are also attractive from spring, when they push out small, beautiful pale blue flowers, through fall, when they often show off some of the best color in the perennial garden.

Amsonia hubrictii, which has the thinnest foliage of all Amsonia, produces stunning gold fall foliage to rival any maple tree. It is also an excellent texture contrast to medium and bold-textured plants, offering exceptional interest all summer, when, in my garden, it serves as an excellent backdrop to a collection of dahlias.

There are several species of Amsonia differentiated mostly by the width of their foliage and their overall size. ‘Midway to Montana,’ a hybrid cultivar developed by Brent Horvath at Intrinsic Perennial Gardens in Hebron, Ill., is a fringed bluestar (A. ciliata) that received very high ratings.

Evaluators also observed several species of butterflies and moths, included snowberry clearwing moths, using Amsonia as a host plant.

Interestingly, two of the worst performers in the trial were two non-native species, including a popular cultivar called ‘Blue Ice,’ which was “extremely susceptible” to rust.

The report also recommended leaving 12 to 18 inches of the hollow stems standing after the annual cutback to provide habitat for native bees.

Unlike most of Mt. Cuba’s trial reports, there was no star. Instead, the report suggests that, “Gardeners merely need to choose a preferred size and foliage texture and make a selection from the growing list of available cultivars and species.”

In other words: Plant some Amsonia. You probably can’t go wrong.

Mt. Cuba Center publishes its native plant evaluations on its website at www.mtcubacenter.org.