Have you ever grown the traditional ironweed? The first time that I met this plant was in 1998. I was amazed that Vernonia noveboracensis could grow to almost 10′ in height. I have since had a special place in my brain for Vernonia because it is a wonderful, native perennial that has striking, purple flowers in late summer. But, it is a huge plant. And if the soil is rich and moist, it can seed around the garden. Besides, there aren’t many plants that can step down a 10′ tall (or taller) perennial.
Fast forward to last year when I first started working at CMBG. I was walking through the garden when I was stopped in my tracks by what appeared to be a purple flowered Amsonia hubrichtii. After looking closer at the flowers, I saw the label that said Vernonia lettermannii. My first thought was, wow, this is cool… a small Vernonia. This would be perfect for the garden. My second thought was wondering if this plant was named after David Letterman. It was actually named after George Letterman, a reclusive botanist who spent most of his life exploring for plants while living in a one-room shack in Missouri.
Letterman’s ironweed is found in the wild along rocky floodplains in Arkansas. It can withstand long periods of drought once established. An established clump can reach up to 30″ in height and width. We cut our plants back after they go dormant each fall.
In late August and into early summer, Vernonia lettermannii is covered with purple flowers. These flowers are sought after by butterflies for nectar. One of the most successful cultivars is V. lettermannii ‘Iron Butterfly,‘ which was introduced by Dr. Allan Armitage from the University of Georgia. This selection is supposed to more upright than the straight species with even more flowers. We have a clump in our Alfond Children’s Garden. I will definitely keep an eye on it this fall to see how it compares to the species.
As you go around your garden this fall looking for holes to fill in your garden beds, consider Vernonia lettermannii for any open, sunny site.
Images: utgardens.tennessee.edu, bustaniplantfarm.com