Ironweed: The Superhero of Fall Plants

Find out why you should be growing this underused native beauty with a hardiness of steel

Vernoniaspp. and cvs.

USDA Hardiness Zones:4 to 9

condition : Full Dominicus to partial wraith ; moist , well - run out soil but adaptable to drying agent and/or gravelly soil

Bloom Time : Mid- to late summer through mid- to late fall

trouble : Powdery mould and rust

Someone lately said to me that ironweeds are ecological plants , not garden plants . This announcement got me thinking differently about these imposing indigen . Is this a vulgar percept among gardeners ? Does my affinity for ironweed unsighted me to their shortcomings ( no paronomasia intended ) ? I remember the first time I saw an ironweed in a garden : It seemed impossibly improbable , but the high poll of purple flowers aflutter with butterflies and bees magnetize me , and it was love at first sight . But since that first glimpse , I ’ve rarely encounter ironweeds in cultivated landscape . At 7 to 12 foot tall , their intimidating size likely unnerves some gardeners and certainly excludes them from pocket-size gardens .

give way this , the interrogation of their garden - worthiness lies at the source of my long - running test . While there are a few distant cousins in the group , many ironweeds are aboriginal to North America . today , the growing interest in pollinators has made aboriginal plants sexy , so it ’s the perfect meter to get to fuck ironweeds a little upright . brush aside their size would be like avoiding the elephant in the room , but I challenge gardeners to take all their other fantastic attributes and give ironweeds a secretive flavour .

Top Performersare Worth the Investment

Trial Parameters

Since 2010 , the Chicago Botanic Garden has pass judgment 17 different ironweeds .

Giant ironweed(V. gigantea ) was the second tallest in the trial , reaching a towering 103 inches . For such a large industrial plant , I expected a much bigger bloom , but , at half an in wide , the purple - violet bloom heads are among the minor . Thanks to Brobdingnagian prime clusters — well over a foot across — elephantine ironweed always redact on a magnificent show , though . The 9 - inch - long , grey green leaf are telling in size , and a tip of purpleness in the topmost ones and stem is a nice dainty . In a large space , silvery gray – leave ‘ Skywalker ’ Amerindic pot ( Sorghastrum nutans‘Skywalker ’ , Zones 4 to 9 ) is a beautiful companion to giant vernonia .

Duration : A minimum of four years .

player : Ten ironweed metal money plus seven cultivar and hybrid selections . Eight of the species were untamed - collected ; we observe variable trait among plants within these species .

Zone:5b

weather : Full sun ; well - drained , alkaline , Henry Clay - loam soil .

handle : Minimal , allowing the plant life to prosper or miscarry under born condition .

Nowadays , the growing pastime in pollinators has made native plants sexy , so it ’s the perfect time to get to know ironweeds a little better .

No other ironweed has the smell or texture of narrowleaf vernonia ( V. lettermannii ) . indulgent , needle - shape leaves insure the stem from top to bottom , yield the works a shaggy show , which can be confused with another Arkansas native , spring - blooming threadleaf bluestar ( Amsonia hubrichtii , Zones 5 to 8) . Come recent summertime , there is no question of its affinity when the stem bakshis branch into large clusters of little purple efflorescence . The habit of‘Iron Butterfly ’ narrowleaf ironweed(V. lettermannii‘Iron Butterfly ’ ) is brusk and less prostrate to opening up in the heart than the species . In full Dominicus , ‘ Iron Butterfly ’ is so compendious , it wait shorn ; in fond wraith , the minginess is not as articulate . ‘ Iron Butterfly ’ is show up up in catalogue and garden centers more and more , attesting to its expectant quality and gardeners ’ desire for something dissimilar . And , let ’s be real , its name is ingenious !

In an objective tryout , there should be no favorites , but Missouri ironweed was mine .

In an objective trial , there should be no front-runner , butMissouri ironweed(V. missurica ) was mine . burnished reddish blue flowers sprout from plump purple buds , put on one of the best shows of late summer I ’ve seen . Its lance - regulate leaf , up to 7 inch long , are fuzzy and silver due to the dense clean hair’s-breadth on the undersides . As a toucher , I never pass Missouri vernonia without caressing the velvety leaf . liken to other ironweeds , I ’ve always thought there is something more refined about Missouri ironweed than its stoutness paint a picture .

New York ironweed(V. noveboracensis ) was my introduction to the genus , so I have a gentle touch for it . Of all the ironweed in the trial , it was the gangliest in its young , although over sentence it develops a inviolable shaggy-haired drug abuse . In autumn , cavorting monarch butterflies are especially brilliant against the deep purple bloom . Its dark green , lance - determine leaves are big — up to 8 inches long , a little coarse , and borne on stiff , purplish stem . New York ironweed had the distinction of continue rust spare during our test — an dimension shared only with narrowleaf ironweed . Although New York ironweed arise course in wet sites , it is adaptable to dry conditions , too .

From a distance , western ironweed(V. baldwinii ) looks a piffling like Joe - Pye dope ( Eutrochiumspp . and cvs , Zones 4 to 9 ) , but its attractive , fishgig - shaped leave-taking — harsh on the surface and softly hairy on the underside — are not whorled like its full cousin ’s . The same white fuzz adorn the arrow - straight stems , which arm in midsummer to halt regal bloom in loose , flattened clusters . The scale of the flowered bracts recurve at the tips , giving the rosette a prickly appearing , but it ’s not at all prickly . Given the smaller prime heads — less than an column inch wide — the floral video display is not as vivid as Arkansas ironweed , but it ’s as bountiful as any vernonia . The upright habit is handsome and narrow — well , at 50 column inch wide , what passes for narrow-minded for an ironweed . Contrary to warning , western ironweed did not spread or create a colony during seven years in the trial .

Arkansas ironweed(V. arkansana ) is readily recognizable by the long , yarn like appendage on its flowered bract , which is undoubtedly the origin of its alternate coarse name : curly top ironweed . violet peak in large heads to 1¼ inches wide look like pincushions atop the magniloquent , stiff stems in late summer . Like other metal money in the tribulation , these plants came from seed that was groundless - collect in the Ozarks ; being seed - grown , foliar and substance abuse traits varied slenderly among the plants . The narrow , willow - similar leaves — up to 7 inch long — were at times dust with former - season powdery mildew and rust . Hummingbirds have always been rare sighting in the trial gardens , but they joined in with the butterfly and bee on this vernonia .

New Kidsto Keep an Eye On

Bringing ironweeds down in size of it was going to materialize , whether through selective breeding or countenance nature have its way . ‘Southern Cross’(V.‘Southern Cross ’ ) is a scant selection from Intristic Perennial Gardens that came from seeded player sown as narrowleaf ironweed . Its drear green , willow - similar leaves are wider , so the nameless parent certainly had broader leaves . The enigma parent pass on some semblance too—‘Southern Cross ’ has purplish stems , and its uppermost leaves have a bronze cast . Bright majestic flowers in heads up to an inch across are plentiful from late summer to former fall . Next to its jumbo cousins , ‘ Southern Cross ’ is almost a dwarf — expected to be only 4 feet tall and wide .

In a “ spyglass - half - empty ” mo , I envisage that the efflorescence of‘White Lightning ’ New York ironweed(V. novaboracensis‘White Lightning ’ ) might be a not - so - middling muddy white like Joe - Pye weed . opine my delight when the flowers opened unadulterated white in late summertime ! ‘ White Lightning ’ is a cum melodic line developed by Jelitto Perennial Seeds , and it bloom the first yr from germ . Like other vernonia , though , the habit is a little sparse the first class or two . We have n’t grown it long enough to achieve full sizing , but it is guess to reach 6 to 8 foundation improbable and 3 to 4 feet wide . So far , the colored green leaves have been rust detached , but powdery mildew has been troublesome at clip . blithely , butterflies and bees make no distinction between white and purple — we’ll see if gardener do .

While waiting to be christened,‘Summer ’s Swan Song’(V.‘Summer ’s Swan Song ’ ) garner a lot of attention as ‘ 20100308 ’ in our run . early on on , we admire the deep red stem and purple - tinged , olive green leaves — the shape comes from narrowleaf vernonia and the coloring from ‘ Plum Peachy ’ tall ironweed ( V. angustifolia‘Plum Peachy ’ ) . Jim Ault of Chicago Botanic Garden ( CBG ) was the expert matchmaker . From betimes to midfall , rich purple flower are plenteous on long , flowering limb — a unparalleled trait of this cultivar . Unlike other ironweeds , the longer branches form an interlocking electronic web that holds the stems upright on even the windiest twenty-four hour period . ‘ Summer ’s Swan Song ’ is the little of the hybrid cultivars right on now , topping out at a compact 36 inches magniloquent and 40 inches broad . Despite the marginal frigid - hardiness of ‘ Plum Peachy ’ , ‘ Summer ’s Swan Song ’ is hardy in Zones 4 to 9 .

Giant ironweed

‘ Summer ’s Surrender’(V.‘Summer ’s Surrender ’ ) , is also the result of careful training — come up from a hybridisation between narrowleaf and Arkansas ironweed made by Jim Ault at CBG . ‘ Summer ’s Surrender ’ has a passing resemblance to ‘ Southern Cross ’ , but , at 48 inches improbable and 74 inches wide , it has a much broad , mound use . The 5 - in - long , linear parting are dingy green and especially lovely ; as a bonus , they are resistant to powdery mould and rust . From ahead of time to belated pin , ‘ Summer ’s Surrender ’ mark the turn of the season with an telling show of colored purple flowers in broad , airy clusters .

Basics

Ironweed 101

Ironweeds are long - hold out perennial that rarely involve part . The unwashed name may be a nod to the iron - like rigidness of the stems or more likely refers to the rusty hairs on the cinnamon - one-sided seeds . Here ’s what else you need to recognise :

Habit : works be given to uprise taller in moist soils , although some are drought liberal once established .

Pests and Disease : Powdery mould and rusting can infect foliage in autumn . Their bitter - try out leave are not toothsome to most mammalian , including deer , but rabbit occasionally browse narrow - folio ironweed and ‘ Plum Peachy ’ marvelous vernonia .

Giant ironweed

Pruning : To reduce flora size , bring down back new stem by half in late springiness ; in our trial , plant were up to 18 inches shorter when shear .

Flowers : Ironweeds are in the aster family but lack their splashy , petal - similar shaft of light florets . rather , upward of 50 or more tubular disk floret gang into compact flowerheads confine by leafy bract that are unique to a coinage and helpful in identification . Some flowerheads assess a foundation across or more .

Pollinators : It ’s nearly impossible for me to project the flower without a mélange of bee and butterfly stroke loom overhead , as they are so much a part of the floral show .

Giant ironweed

Foliage : The drab green foliage tends to be lance regulate but can be willow - corresponding or feathery . foliage sizing heighten the bigness of some ironweed ; for example , giant ironweed tops out at 8 feet tall , but the 10 - inch leaves make it seem even larger .

Seed Heads : Deadheading reduces unwanted seedlings ; however , if leave in blank space the seedheads tote up special interest in late fall and in wintertime .

Ironweed Trial Result

Rating key

★ ★ ★ ★ Excellent

★ ★ ★ salutary

‘Iron Butterfly’ narrowleaf ironweed

★ ★ Fair

★ miserable

Plant height includes heyday .

Missouri ironweed

Richard Hawke is plant rating coach at the Chicago Botanic Garden .

Photos : Marianne Majerus / Marianne Majerus Garden Images , Nancy J. Ondra , Michelle GervaisPhotos : millettephotomedia.com , Courtesy of N.C. State Extension , Courtesy of Chicagoland Grows , Jo[email protected ] , Intrinsic Perennial Gardens , Courtesy of Jelitto Staudensamen GmbH , Courtesy of Chicagoland Gardens

Sources :

New York ironweed

Laporte Avenue Nursery , Fort Collins , CO ; 970 - 472 - 0017 ; laporteavenuenursery.com

Pine Ridge Gardens , London , AR ; 479 - 293 - 4359 ; pineridgegardens.com

Prairie Moon Nursery;Winona , MN;866 - 417 - 8156 ; prairiemoon.com

Western ironweed

Prairie Nursery , Westfield , WI ; 800 - 476 - 9453 ; prairienursery.com

o.k. Gardening Recommended Products

Monarch Butterfly Rescue Wildflower Seeds 4 oz .

Arkansas ironweed

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Organo Republic 16 Perennial Wildflower Seeds Mix for Indoor & Outdoors

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