Wildflower Wednesday: How Ironic

Tall Ironweed (Vernonia altissima), like the other Ironweed species, has many virtues and is a good plant for the true native plant enthusiast.  Which is to say, if you are looking for a plant that delivers a major ornamental punch proportionate to the space it takes up, Ironweed may not be for you.

2013-08-11 11.44.26 ironweed

Tall Ironweed grows 5-8′ and will form large clumps, especially if you let it self-sow. Some related species will not grow quite so tall.

The red-pink flowers are showy, but not very long-lasting. My own Tall Ironweed is blooming for the first time this year and has not yet formed a large clump. Flowers began opening in late July and were pretty well done by the last week in August. The Missouri Botanic Garden website sniffs that other than the flowers, ironweeds are “somewhat unexceptional” as ornamentals.

7-22 Ironweed

Tall Ironweed is a very good plant to have if you are into wildlife gardening and want a diversity of native species that are beneficial to pollinators. Ecologists have recognized the species as being particularly attractive to native bees, and butterflies are drawn to the flowers as well.

It is possible that Ironweeds will emerge from their “somewhat unexceptional” ornamental status. The Chicago Botanic Garden is testing a number of Vernonia varieties for home garden use.


Also, Tall Ironweed is a pretty easy care plant without serious insect or disease problems. It likes moisture, but is adapts well to ordinary garden soil. Despite the name, I find that it does require staking. Most Ironweeds want full sun, Tall Ironweed can tolerate part shade.

Actually, there is some confusion about the origin of the common name. Some people thinks it refers to the sturdiness of the stems, others to rusty colored flowers or seeds. The genus is named after a 17th Century English botanist, William Vernon.

I had a funny experience with my Ironweed. I planted it in the fall of 2011 but it seemed invisible in 2012. Suddenly this year it is popping up 8′ tall and blooming.

Have you tried growing Ironweed?

Wildflower Wednesday is hosted by Gail at Clay and Limestone. For more wildflowers, check out her site.

63 Comments on “Wildflower Wednesday: How Ironic

  1. Haha…it’s so true! I’m happy to see other people growing it…even if it’s not the showstopper that many people seem to demand of each garden plant…it has a nice dignified beauty (but yes, it needs staking, sadly). Still, I find those electric purple/red flowers wonderful at this time of year. I’m trying one of the shorter varieties this year, Vernonia ‘Southern Cross’. It’s supposed to top out at 3-4′ tall and wide…and looks quite a bit like Amsonia until it blooms. So far, I’ve been pretty impressed.

  2. I’m growing Veronia lettermannii for the first time and I am loving it! It is like a better looking verbena bonariensis. Tons of pollinators and a pretty deep purple. My only problem is that it’s supposed to be compact at 2×2 and my is about 5 feet tall already.

    • I never heard of this species – it’s not listed in the catalogs I usually order native plants from. It does look more floriferous. I see there is a cultivar ‘Iron Butterfly’. Is that what you have?

      • Yup, that’s it. I had forgotten that name. Tony Avent at Plant Delights (where I bought it) calls it something like Late Night with Ironweed, so I wasn’t thinking of Iron Butterfly.

  3. Jason, this plant is growing here everywhere, sometimes I find it in my garden too. Ironweed is nice weed, but I don’t like it in my garden!

  4. The tall ironweed came with the property here. It took several years for me to figure out that cutting it by two thirds in May would result in shorter, bushier plants that would bloom later. It looks wonderful with the goldenrod and various asters with some tall grasses thrown in for texture. The pollinators go gaga for this mix.

  5. Haven’t tried it up to now but same thing happened with my Cephalaria gigantea…sometimes plants have a mind of their own, don’t they?! I think the ironweed is a beautiful plant and if it it is good for pollinators just as well.

  6. What an interesting plant, I haven’t ever grown it but great to hear it’s good for the pollinators.xxxx

  7. I am growing vernonia glauca, which I ordered because it’s supposed to be more drought-tolerant than the NY kind. (I went for Ironweed also because the book of that name by William Kennedy was one of my father’s favorites.) I have whacked it back, staked it, caged it and had serious conversations with it, but no matter what, the vernonia collapses onto the neighboring asters. However, I would say it is up there with hyssop in terms of attracting insects, bees and butterflies. I’m expecting it to bloom in the next week or so and I can’t wait. Looks great next to helianthus ‘Lemon Queen’ (another plant I can’t control).

      • Yup, it flops even though I cut it back. Next year I will cut it back even more. Part of the problem is probably that my sun is very directional. I have a small yard with fences that create shade at certain times of the day.

  8. Although I’ve never planted it, It pops up in my yard every single year. I’m not crazy about it in my space because it always pops up right in front of the flower beds. I’m sure it would look good in the back but I don’t know if it likes being transplanted. I end up cutting it short and putting it in a vase. The blooms are very short lived that way though.. oh well! 🙂

  9. I put V. lettermanii in this year like a couple of your other commenters. I think I’m going to love the smaller size and bushier shape (I hope it doesn’t get as tall as Sarah’s!). V. glauca has been pretty but the blooms don’t last very long (as you mentioned) and they come in the middle of summer. I will have to try Fairegarden’s suggestion to cut them back hard and see if they’ll bloom later next year.

    • Yes, If I say so myself, this has been one of the more helpful and informative comment threads I’ve had on this blog – I learned a lot.

  10. I have it in the back of my Long Border. I’m not too impressed with it. I probably have it overcrowded, but it does get full sun. Although it has sufficient moisture, I have a feeling it would enjoy a lot more than it gets and lack of moisture may have had something to do with its performance for you last year. I’m not so sure it is a fan of extreme heat either.

    • The ‘gateway’ joe pye is in the same bed and I give it extra water, I could do the same for the ironweed. I’m not thinking of taking it out this year, I’ll give it at least another couple of years to show what it can do.

  11. I was going to say that I was surprised the hybridizers hadn’t gotten ahold of this one but after reading the comments I see that they have. The USDA distribution map says it grows here but I’ve never seen it.

    • I’ve seen some attractive stands of ironweed in the demonstration gardens at the Chicago Botanic Garden, not sure what varieties they are testing.

  12. I have never had luck getting Iron weed started here. I would love a stand of it. Happy WW.

  13. I’ve admired these plants in native plantings for many years, but have yet to try one in my own garden. How funny that yours didn’t appear last year, but this year grew so tall. I guess it skipped the “creeping” stage and went straight to “leaping”:)

  14. I haven’t tried planting it, but I have seen it around the area. I really like the color of the blooms, but if they don’t perform the greatest in the garden maybe I’ll just enjoy the plant in the wild. Thanks for the info about your experiences with it.

  15. I always thought it looked nice enough in the wild, I never realized it was somewhat underwhelming in the garden. I’m going to make a point of taking a closer look at the wild ones around here. Maybe I can find one that’s a little more exciting!

  16. I’ve been growing what I think is the kind native to my general area (Nebraska), and not the giant kind. I was thinking about getting one of the giant ones for a butterfly garden I am helping with, but found some of the shorter ones yesterday for it. If I had more room, I would consider trying the taller one.

    • I don’t think the butterflies will care about the height. The taller one is an interesting choice for something really vertical, it goes well with Joe Pye Weed.

  17. Not familiar with ironweed but was going to chime in on breeding work potential which I still think would be very fruitful.

  18. I have never seen ironweed, but it reminds me very much of Verbena bonariensis. I imagine the tall one looks lovely swaying in the breeze.

  19. decided I just had to have it after seeing a patch at the Royal Botanical Gardens Kippax wildflower gardens in Ontario. Such a beautiful colour of purple. I’ve got seedlings ready to put into the ground and now am a bit trepidatious thinking that I’m unleashing a monster, however unexceptional… Will put it with all its tall friends, stand back and hopefully in a year or two, I’ll have a photo of it cavorting with some yellow, whites and pinks.

  20. I’ve never tried growing this but I think it looks nice in your garden and like you say if it has benefits to wildlife then I give it the thumbs up!

  21. Hi Jason, I still wonder why it is called Ironweed, but we also have a Vernonia genus here although very small unlike that one. On the other hand we have an ironwood, which is very tall and true to its name cannot be just sawed by any other ordinary saw! It really lives up to its name as ironwood!

  22. I grow Vernonia fasciculata here in north-central Illinois and love it. No flopping. Has turned chocolate brown now — not unattractive.

  23. I just added Threadleaf Amsonia, Vernonia lettermanii…it looks just like amsonia before it blooms. Mine still hasn’t bloomed but I’m anxiously waiting. I don’t have space for the tall ironweed—yet…(that could change, down the road!).

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