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
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