Plant of the Month: Zigzag Iris

Presented by Iris Poteet
June 12, 2023

Botanical name: Iris brevicaulis
Common name(s): Zigzag Iris, Leafy Blue Flag
Family: Iridaceae

[MUSIC—EASY AND FUN]

[Iris] The plant of the month that I volunteered to talk about is Iris brevicaulis. You can guess why I chose this one. Iris brevicaulis is also called the Zigzag Iris or the Leafy Blue Flag. And, as you know, flag is another name for iris in general.

Formerly, this was called Iris foliosa and “foliosa” meaning “leafy.” Brevicaulis means short and that’s one of the reasons I chose this, because I’m short! So, the name really appeals to me.

It is one of five species of Louisiana iris. It grows in swamps and wet meadows.

I really liked this botanical print that I found that shows you not only the blossom, but also the sepal and petal and the seed pod and then the seed.

The Iris brevicaulis has multiple flowers on a single stem but the stem is unusual in that it’s a zigzag and you’ll see that in another photo later. It varies in shade from blue to a really deep blue violet and there’s even a white version. It may have two terminal flowers on the stalk. Mostly you’ll see that the flowers are hidden down among the leaves as you see in this photo. So, there’s the flower here, but there’s also one over here and one further back. You see how the flowers are down low on the plant in the leaves. And for size, the bloom is about the size of most irises—most of the Louisiana irises—but you can see here’s the leaf of a Tropical Sage for comparison.

The bright green leaves are lax and arching. You’ll often notice that the leaves curve and hang over down to the ground. It’s shallowly rooted, but like the other Louisiana irises it has these branching rhizomes, so it can form large colonies. And then sometimes the stems get rather heavy, and they can become decumbent meaning that they lie down on the ground.

The distribution of the Iris brevicaulis is mostly in the southeast, but as you can see it goes as far north as Ontario, where it has become extinct. I had to look up the key for the BONAP maps because I was a little confused by the color coding here, but you’ll see that in Texas—Texas is colored the dark green meaning it’s a native that occurs in Texas—but it’s showing that the color is more of a turquoise and that means that it’s adventive in the state meaning that it was not necessarily native or found in the state until after the time of Europeans. So, they think that mostly in the state of Texas it’s naturalized. Now, historically I kind of wonder if it’s because people just weren’t looking for it at the right time in the right places because you would think that the habitat is so similar to that of Louisiana in the Piney Woods and elsewhere that it would have occurred here. So, it is native, present and not rare in those states where you see the bright green counties.

And it’s also present but rare in the counties that are highlighted in yellow like in Georgia, Florida and Mississippi. And as I was reading, I was finding that the native irises in general are becoming very, very hard to find in the wild. So, keep your eyes open and those of you that use iNaturalist please post your observations.

I went to iNat and looked for observations in our area to see if I could find some that were in places that might not have been cultivated. A lot of our sightings are in parks and areas that are pretty well populated, and you think that even if they were found in the wild it may have been naturalized from plants that were brought there. So, then I dug a little bit further and I found this one sighting along the east side of FM 523 which does not appear to be a cultivated area. And this is pretty amazing to me because he found not only the purple, but he also found the white versions in the same area. Wow! Isn’t that so cool? I love that.

For cultivation down here, the botanical print that you see on the right, you can see the zigzag nature of the stem and why it’s called Zigzag Iris. It’s the hardiest and most adaptable of the Louisiana irises. And for that reason, it has been used in the nursery trade for cultivation. So, it has been crossbred with other species of irises.

It prefers sun, but it can tolerate part shade, grows about 10 to 12 inches. Could grow as high as two feet, but, as I said, it tends to kind of fall over, so it doesn’t have a very erect posture. It grows well in places where the moisture is high in fall, winter and spring. So, like in my yard I have native plants in my backyard I don’t water, except for potted plants, but the plants that are in the ground I don’t water and my Iris brevicaulis survived last year’s summer drought and what popped up again in the spring had beautiful blooms. One of the previous pictures was from my yard.

It can be propagated by division of rhizomes when the plants are dormant.

It’s pollinated primarily by bumblebees, which makes sense. You know our native plants are often pollinated by our native pollinators, so you would see bumblebees and sometimes hummingbirds.

You harvest seeds from the mature seed pods—you saw a picture earlier of the seed pod—but germination is very slow. It can take three to 12 months for seeds to germinate. I have not tried growing them from seed. In fact, I have not found seed. I’m looking at my plants, but I’m afraid they may not have been pollinated, so I’m not sure I’m going to get seed. But when grown from seed, it may take three to five years to flower.

So, I’ll leave you with some additional resources. If you go to iNaturalist and just search on the species Leafy Blue Flag or Iris brevicaulis you should find other sightings there. The website Zydeco Irises was particularly helpful as I was preparing this. And then I have a link here to an article on Louisiana Irises in the wild that was really fascinating to me. Mostly found in Louisiana, but it’s been a few years, so some of them may have even disappeared since then. The USDA website had good information, but I did find that there was very little information on the Lady Bird Johnson Wildflower website and that’s why I have not listed it here.

If you want to reach out to me and learn more along with me—there was a lot here that I didn’t know that I learned as I was putting this together—but if you want to learn more, you can contact me at irisbrevicaulis at gmail dot com.

Thank you!

[MUSIC—AND THAT’S IT]