Bluestar

Amsonia in bloom at the Toronto Botanical Gardens

I first got to know many of my favourite perennials in my mother's garden when I was a young girl. 

Bluestar, Amsonia is a plant I was not familiar with until we moved to our present home in Huttonville a little over fifteen years ago. Since that time I have come to appreciate Amsonia for its starry spring flowers and the marvellous color of its fall foliage.

Amsonia in my front garden

My garden

In my garden, a well-established clump of Amsonia has a place next to a Baptisia. Occasionally, one will bloom without waiting for the other, but most years, they work together to put on a fine display. 

I have come to love this mix of sky blue and deep indigo flowers. 

The second place I have Amsonia is just inside the white picket fence. Here it blooms alongside a Gas Plant, Dictamus albus. 

Here are a few other combinations from the Toronto Botanical Gardens: Bluestar, A. tabernaemontana + Baptisia 'Purple Smoke'

 Bluestar, A. tabernaemontana + Purple Alliums at the Toronto Botanical Gardens

Bluestar, A. tabernaemontana + Salvia at the Toronto Botanical Gardens

Toronto Botanical Gardens

Bluestars are slow growers that take years to reach a decent size. The good news is they are long-lived perennials that prove to be well worth the wait. When mature, Amsonia form broad, mounded plants that take a fair bit of space, so keep that in mind when you bring a little potted plant home from the nursery. 

Unlike many other perennials that die back at the centre of a clump after a few years, Bluestars have strong, uniform growth.

When cut, the stems of Amsonia exudes a milky sap that I find it a bit irritating when it comes in contact with my sensitive skin. So I wear gloves when I cut it down in the late fall. One great thing about this white sap is that it makes the plant unattractive to insects, deer and rabbits. 

Moving or dividing established Bluestars can be a challenge as they have a woody rootstock that can be hard to dig up.

Toronto Botanical Gardens

After flowering, the foliage stays attractive throughout the summer and provides nice textural interest. In the fall many species become a vibrant gold when grown in sunny, warm locations.

My garden

The seedpods on my Bluestars are long pods that open as the seeds mature. 

I am always slow to get around to cutting the plants down in fall, but so far I haven't experienced any problems with prolific self-seeding.

Amsonia ciliata 'Spring Skies'

Varieties of Blue Stars, Amsonia to watch for:

Arkansas or Threadleaf Bluestar, Amsonia hubrichtii is native to the southern USA. It has soft feathery leaves that resemble a bottle brush. The plant forms a billowy mass that is quite shrub-like. Amsinia hubrichtii has pale blue flowers in spring. This plant is happy in well-drained average to poor soil. Full sun or very light shade.  Height: 60-90 cm (23-35 inches), Spread: 75-90 cm (29-35 inches). 

Willowleaf Bluestar, Amsonia tabernaemontana is native to Eastern North America. It has slender, willow-like foliage and light blue star-shaped flowers in spring (blooms approximately for 3-6 weeks). This plant performs well in a range of soil types, but prefers average to moist growing conditions. Full sun or light shade. Height: 60-90 cm (23-35 inches), Spread: 75-90 cm (29-35 inches). Hardy to zone 3.

Amsonia illustris is native to southeastern North America. The leaf shape is similar to A. tabernaemontana, but is shiny and leather-like.

Amsonia ciliata is a low growing type of Amsonia that has pale blue flowers. When planted in full sun, its fine foliage turns amber in the fall. 

The Hybrids:

Amsonia 'Blue Ice' has foliage like A. tabernaemontana, but on a more compact plant. Dark blue buds open to soft blue flowers in early spring. This hybrid blooms for 4-6 weeks. Height: 35-40 cm (14-16 inches) Spread: 45-60 (14-18 inches).

Amsonia 'Seaford Skies' has fine, pale blue flowers and bright yellow foliage in the fall. Height: 35-45 cm (14-18 inches) Spread: 45-60 (14-18 inches).

Amsonia ciliata 'Spring Skies' another compact variety that has willow-like leaves and blue buds that open into soft blue flowers. Height: 45-60 (14-16 inches), Spread: 45-60 (14-16 inches).

Plant type: Perennial

Height: Depending on the cultivar: 35-90 cm (14- 35 inches)

Spread: Depending on the cultivar: 45-90 cm (18-35 inches)

Flower: Shades of blue (sometimes the flowers fade to near white when they mature in full sun).

Bloom period: Early to mid-spring

Leaf: Provides great fall color.

Light: Sun or very light shade

Growing from seed requires cold stratification.

Companion Plants: Baptisia, Alliums, Salvias, Columbine, Geraniums, Peonies, Iris to name but a few.

Divide: Blue star has a woody rootstock that makes division a challenge. Divide in early spring before new growth starts. Propagate by stem cuttings in early summer.

Notes: Amsonia has a milky sap that makes it unattractive to deer and rabbits.

Problems: Virtually problem free!

USDA Zones: 4-9 with the exception of A. tabernaemontana, which is hardy only to Zone 3