Sunday, July 25, 2010

Common Ironweed - Vernonia angustifolia


Common ironweed (Vernonia angustifolia) is a similar version of giant ironweed (V. gigantea) with narrower leaves and shares many of the same characteristics and uses.  It is found throughout the northern two-thirds of Florida, but is confined to the Southeast Coastal Plain in the U.S.  As such, it is a true southern ironweed.
Although sometimes also referred to as "tall ironweed", its Latin name draws reference to its relatively narrow leaves.  I believe this is a far better distinguishing characteristic between it and its "giant" cousin as common ironweed is nearly as tall in most settings as giant ironweed.
Common ironweed is deciduous and emerges in early spring; forming a basal rosette of elliptical leaves with serrated edges.  The linear flower stalk is evident by late spring and mature by summer.  The leaves along the stalk are quite narrow.  At maturity, the stalks are 2-3 feet tall.
The flowers of common ironweed are similar in color and size to giant ironweed, but the corymb is often a bit smaller in diameter.  The flowers are a stunning lavender in color and quite attractive to butterflies and other pollinators.
Common ironweed is most commonly found in moist flatwoods where it receives ample sunshine and above average moisture.  I have not found this species to be especially drought tolerant in my own landscape, though well-established specimens will "hang on" for some time during droughty periods.  Extended and/or repeated drought, however, is difficult on them and eventually kills them if supplemental water is not provided.
Use this species in a mixed wildflower garden and combine it in the middle portion of the landscape with other medium-tall species such as grassleaved golden aster (Pityopsis graminifolia), Garber's blazing star (Liatris garberi), red salvia (Salvia coccinea), Florida tickseed (Coreopsis leavenworthii) and skullcap (Scuttellaria integrifolia) that also tolerate slightly moist (not wet) conditions. 
For all its beauty and usefulness, common ironweed is only rarely offered for sale by commercial nurseries in Florida.  We intend to propagate it at Hawthorn Hill from seed we have collected this summer and hope to have specimens for sale by late spring 2011.  Inquire if you are interested and we will set some aside for you - assuming we have good germination. 

5 comments:

  1. Use some words that kids under stand for projects or just to learn!

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  2. Hi there - i planted some vernonia; i believe it was the angustifolia because the leaves are thin but it was sold as "giant ironweed." Anyway, the plants look pretty bad right now. do they need to be left alone in the unattractive time, or can they be cut and still reappear next spring?
    Thank you!

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  3. First, I find that there is a lot of mislabeling of the Vernonias in the native plant industry. Many times, I have seen V. angustifolia labeled as V. gigantea and vice versa. They both get to be the same height at maturity and it's only foliage differences that easily separate them.
    Secondly, both die back to the ground about this time of year. You can cut back the dead stems if they bother you, but dead stems provide over-wintering habitat for some bees. I regularly leave many of my dead stems until early spring for that purpose.
    Third- thank you for your kind words about my books. I'm hoping to have the third one published in about a year - it is about using natives to landscape shady areas.

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  4. Great information about the vernonia - but the big news is the new book. That will be great for people (like me) who have shade and are stymied by it. I will be watching for it - all the best

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  5. Did you have luck with this ironweed?

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