Wednesday, February 24, 2016


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 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'

Toronto Botanical Gardens

Bluestar, A. tabernaemontana + Purple Alliums

Toronto Botanical Gardens

Bluestar, A. tabernaemontana + Salvia

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 milk 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 root stock 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 look 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 milk 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


  1. What a lovely plant - I've never heard of it before. Another one for my list!!

  2. I just this plant on another garden blog and immediately ordered some! I think I'm going to love it even if it does take a long time to establish.

  3. It looks like we are profiling some of the same plants this year. I have a few small amsonia that I can't wait to see establish themselves. Just love it.

  4. You had me at 'unattractive to deer'. What a pretty blue!

  5. What a beautiful flower! Blue flowers always seem extra special.

  6. So now I know what this is!! :-)
    We have a lot of them growing near the outflow of our pond.
    None of ours are blooming now though.
    It is going to be a while yet before we see flowers here.

  7. Your post reconciled me to Amsonia. It bloomed for me for the first time last year (i grew it from seed) and I was wondering whether to keep it or not as the blooms are so small. Looking at your pictures, I see that what I need is a larger clump of them.

  8. What a lovely plant! I wonder if it would be too hot here. And deer don't like it, they are a real problem here. They just eat everything !

    1. Amsonia are native to different areas of the States, so I would think they can take a fair bit of heat. Maybe try Amsonia hubrichtii if it is heat+dry conditions and Amsonia tabernaemontana if you have heat+moist conditions.

  9. Another nice perennial for my zone 5 ,Jennifer. I read about Amsonia but didn't grow it in my garden yet.

  10. It looks like a gorgeous plant for adding some contrast to the garden. I'll keep an eye out for it. I'm not sure I've ever seen it in person.

  11. Can't tell you how much I appreciate this post. I've saved pictures of Blue Star Amsonia and plan to add it to my garden, but I didn't know anything about it. Now I'll look like I know what I'm doing. Your photo of it with Baptisia is beautiful. I LOVE blues in the garden.

  12. Lovely flowers
    Lovely photo's

    Always a pleasure to visit your blog
    Have a lovely weekend

    All the best Jan

  13. I appreciate especially the part "unattractive to rabbits". :)
    What an interesting and beautiful plant! Your photos are wonderful.
    Have a great week ahead!

  14. I have grown to love Amsonia too. A. hubrichtii is my favorite due to the fragrance of the flowers and its qualities as a foliage plant. It colors beautifully in the autumn whereas my A. tabernaemontana doesn't color at all.

    Your baptisia is so blue! I have one that is nearly a royal blue but none are such a medium/deep true blue as that one.


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