Tuesday, September 18, 2012

Fantastic Native Cultivar: Amsonia 'Blue Ice'

Amsonia 'Blue Ice' in my garden late April next to Nepeta 'Walker's Low' & Phlomis

Who needs a compact, attractive, tough-as-nails perennial that--by the way--is gorgeous in two seasons?  Yes, everyone.  Then let me enthusiastically endorse Amsonia tabernaemontana 'Blue Ice.'

The horticultural world is still rightfully swooning over its feathery cousin, Arkansas Amsonia (Amsonia hubrichtii), recent winner of the Perennial Plant of the Year.   I will make the claim, however, that Amsonia 'Blue Ice' may be the more versatile and durable plant.

Amsonia 'Blue Ice' was discovered in a seedling block of Amsonia tabernaemontana at White Flower Farm in Connecticut.  It sports the same broad leaves of the species, giving it a handsome texture to contrast with finer-foliaged plants.  But it seems to be more compact (12-15 inches in height), longer blooming (three weeks + in my garden), and has this incredibly dark blue color of the bud of the flower.  Dark blue is incredibly rare in perennials.  The dark blue buds have this incredible shadowing effect underneath the lighter blue periwinkle-like flowers.  In the mid-Atlantic, it bloomed late April through early May.

Dark blue buds shadow the lighter blue open flowers of Amsonia 'Blue Ice'

Amsonia tabernaemontana is a member of the dogbane family (Apocynaceae).  Like other members of the dogbane family, it has a white, milky sap that is toxic to mammaliam herbivores--perhaps making this a deer-resistant plant?  (Have others of you grown this plant in deer country?  I'd be curious to know how it fares.) It grows natively in rich open woods, rocky woodlands, limestone glades, and moist sandy meadows.

'Blue Ice' is a hybrid, but the exact parentage of this cultivar is still unknown.  Tony Advent of Plant Delights Nursery guesses it is a cross with the taxonomically-debated dwarf Amsonia montana (which most nurseries seem to categorize as Amsonia tabernaemontana 'Montanta').  Others have wondered whether it is a cross with the Asian Rhaza orientale, which after looking at images of Rhaza, seems highly plausible.  Whoever the papa is, Amsonia 'Blue Ice' has proven to be incredibly tough.  I planted it where it spills over a public sidewalk.  The heat off this sidewalk regularly tops 95 degrees for weeks in the summer.  And yet the foliage remains steadfast and handsome.    Based on my two year trial, I'd recommend it as a replacement for groundcovers. 


The foliage of Amsonia 'Blue Ice' in the midsummer heat near the U.S. Senate office
In the fall, this Bluestar turns a golden yellow, though  not quite as brilliant as its Threadleaf-cousin (A. hubrichtii).  Fall color was ok the first year, and much better the second year.  The warm yellow autumnal foliage is nice in combination with low grasses and native deciduous shrubs.


The fall foliage of Amsonia 'Blue Ice' is good, though not as strong as A. hubrichtii

The success of two U.S. native Amsonias (A. tabernaemontana and A. hubrichtii) should convince plant breeders to explore more of this wonderful genus.  Piet Oudolf has used Amsonia tabernaemontana var. salicifolia to great effect on projects such as The Highline and the Lurie Garden.  This variety differs from the species in that is has narrower more lanceolate leaves that makes it more willowy in texture.  There are at least 22 known species of Amsonias--most native to North America--and many of them have horticultural potential.  Southeastern natives Amsonia illustris and Amsonia ludoviciana are two others worth noting.  I'm particulalry interested in the Louisiana native A. ludoviciana for its compact habit, heat tolerance, and whitish, whooly undersides.  Could be a great native groundcover that might have some deer tolerance.  Plant hunters and breeders, get to it!

Amsonia hubrichtii in fall is incredibly dramatic

20 comments:

  1. I have Amsonia Northwind Select which is a cross between Montana and Hubrichtii only sold at Northwind Perennial Farm. It is in its second year so we will see how it looks in the fall this year.

    I also have Blue Ice in its first year and was told it may be renamed because it has been identified as a Rhaza and is undergoing genetic testing. None of this matters if it is a great plant.

    Eileen

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    Replies
    1. That's fascinating. I would not be surprised if it were renamed.

      I can't imagine a montana/hubrichtii cross! Sounds interesting.

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  2. I don't think anyone lives in an area with greater deer pressure than I do and my Amsonia hubrichtii has survived six years (knock on wood) totally exposed. On the other hand, it struggles in my heavy clay, though I have it in one of the better drained areas of the garden (at front of house, outside the deer fence)where it has finally grown into a respectable mound. Amsonia 'Blue Ice' would be a miraculous ground cover in the main garden--IF it can grow in heavy wet clay. Any advice?

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    1. I think it's worth trialing. The part of my garden its in is heavy wet clay and it seems to be doing well. In fact, so much of the D.C. area has that heavy clay, and everywhere I've seen it, it looks great.

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  3. I grow Amsonia 'Blue Ice' in northern Connecticut and the deer (I have plenty) do not touch it. It has all the attributes you describe, including fabulous golden fall color in my garden. Bloom color is distinctly royal blue tending to purple.

    But do not attempt to move a clump. I tried, and it was the worst job. The plant simply would not release and I chopped it and hacked it and came away with shredded stems with barely a root attached, which I did replant with no hope of any surviving. They regrew beautifully! It is a great, tough groundcover here, and spreads and fills out (slowly) on its own. Give it room to expand in its space rather than trying to move it!

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    1. That's great to know, Laurrie. I'm always extra cautious with deer, so it's great to know that one has survived fory ou.

      I was actually planning on transplanting a bunch soon, so your advice is timely and helpful.

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  4. I have a very well established and quite large Amsonia hubrichtii, which looks just as dramtic in fall as Thomas's photo above. As I prepare my house (and garden) for rental, it occurs to me I might move it down the road to the new old garden. I assume fall would be a fine time to attempt it. Given the above post, I'm hesitant but not too hesitant.
    I could probably get 4 good sized plants from this one. Should I cut the folliage back right after transplanting (assuming I can get it out) or allow to die back? What do you think?

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    Replies
    1. I'd be tempted to wait till early spring to move it. Transplanting herbaceous plants is best when the plant has time to regenerate new roots to replace the damaged ones. It's early enough in the fall it probably would be fine, but if you can wait till March, that's when I would do it.

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  5. I have some 'Blue Ice' in my backyard and it is just finishing up its first season. I'm eager to see the fall color come on. I also have the straight species A. tabernamontana.

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    1. I had high expectations for fall color after seeing A. hubrichtii and it was good, but not great. For some reason, it was much better the second season. I wonder if the straight species has better fall color?

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  6. Whether forest Z 7 or desert z 7, plants and posts like your's give hope for all we *can* do here, where palms are limited, and we just can't have Florida or Phoenix! There's such a wealth of choices, even if we have to collect the seed ourselves...

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    1. Almost too many choices! In some ways, I wonder if it would be better to be a landscape architect 100 years ago when you were limited to what people you can find.

      Are you doing much seed collecting? That's the real way to grow a garden!

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    2. 15 years ago many native plants were not even available here for sale or to spec. In fact, I collected seed of some of our local natives, grown by a large wholesale grower in Arizona to be shipped back as container stock, since local growers could care less! Sad, eh?

      Quercus grisea, Quercus turbinella, Parthenium incanum, Nolina texana, etc. I haven't collected seed since 2003, but I should do it again...tho I may have to start a nursery to sell them. Or I might play Johnny Xeriscape and sneak some seed into places where they can colonize. I have some bags of mesquite and other choice native "thug species" just for that.

      Maybe a weekend sowing expedition is in order?

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  7. I absolutely adore Amsonia hubrichtii...and have been curious about the hybrids that are out there. Even though I love how BIG and voluptuous A. hubrichtii is, it's definitely not easy to squeeze one in just anywhere...so it's nice to have a smaller anternative! I'll have to keep an eye out for this one, now that you've given it such a good recommendation. I would love to use them in my hell strip...especially if the fall color is anything close to A. hubrichtii :-)

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    1. It's definitely a space-efficient Amsonia. Fall color is definitely not as dramatic as the hubrichtii, but the spring blooms are way more interesting.

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  8. Thanks for sharing another great post about Amsonia 'Blue Ice, Thomas. I wonder what it would look like when its being planted using garden pots or planters like using Fibreglass instead of cultivating and growing it on ground..Their flowers are amazing. Keep posting wonderful articles - they are just truly amazing

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  9. I've seen many blue ice plants and they look great especially in community gardens. Great post - keep them coming.

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    ReplyDelete
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