Plant of the Month: Sedges

Presented by Nancy Saint
July 13, 2020

Botanical name: Carex sp., feat. C. cherokeensis, C. leavenworthii, C. texensis, C. flacca
Common names: Sedges, feat. Cherokee Sedge, Leavenworth’s Sedge, Texas Sedge, Blue Sedge
Family: Cyperaceae (Sedge)

[MUS—EASY AND FUN]

[NANCY] We’re talking about sedges but I learned a different rhyme:

Sedges have edges,
Rushes are round,
Grasses have joints,
When the police aren’t around.

There are many versions of this little ditty, but it is important and helps you identify an unknown plant that is grass-like if you can feel the three edges, the three corners, or, if you cut it in half, you can see the triangle that the stem forms.

One thing we all know about sedges is that Deep-rooted Sedges are bad. So, we know a little about the genus Carex or sedge and the sedge family Cyperaceae. Deep-rooted Sedge is Cyperus and is a native to South America. It was accidentally introduced into the United States around 1990.

Man, so it’s, it’s covered a lot of ground since it arrived. It invades disturbed areas throughout the southeastern United States. We’ll be tonight talking mostly about our native sedges in the Carex genus and ones that will be useful in our landscape here in our area.

I will start with one that is more familiar, Cherokee Sedge or Carex cherokeensis. It can be used in prairies, rain gardens, ground covers, natural areas, and as an alternative to traditional plantings.

Those who volunteer out at Armand Bayou might be aware that a lot of their shade grounds are covered with Cherokee Sedge. Now, there people do mow it. Kind of continually, I guess, so it’s pretty short out there. Its natural height would be 12 to 18 inches.

And all these native sedges are cool season grasses, which means that they do their growing during the winter. So, most of these are clumping, as opposed to running, and are very controllable in your yard.

The texture of the Cherokee Sedge is quite coarse. The flowers are small, and the wheat-like seed spikes that follow gracefully droop, which are helpful identifier for the Cherokee Sedge. It can be found in the trade occasionally.

So, let’s take a look at the overall world of the sedges. Okay, we’re in the plant kingdom and the family is the Cyperaceae. And there are at least 70 to 100 different genuses in that family. So, we’re going to cover the Carex genus, which are the sedges. And there are probably 500 species in the U.S. and 2,000 worldwide.

Then the genus Scirpus, bulrushes. Cyperus is the Deep-rooted Sedge and the nutgrass. The Eleocharis, if you’re working with any of the wetland area you’re familiar with the spike rushes. And the Rhynchospora, the beak rushes, which Whitetop Sedge is a member of that, and it’s a good wetland indicator if you’re out walking the prairie. You can find those little potholes.

Okay. This is the picture of Carex leavenworthii. Actually, they’re all the same picture but I just call them something different. No, not really. This is different. It forms tight clumps, about 10 inches tall and 18 inches diameter. The foliage is very narrow and it’s a lush vibrant green in my yard. It does seed around and would even make a great no-mow lawn, perhaps. They’re happy in the shade to part shade, and not too fussy about water. So far this summer, they’re hanging right in there.

The Leavenworth’s Sedge was named in honor of M.C. Leavenworth who was a botanist and an Army surgeon in the 1800s. One source suggested that the plants be cut to the ground during late summer to encourage fresh new growth through the winter. I think I’m going to try this on some of my sedges.

This is the Texas Sedge or Carex texensis, which is really more common in central Texas but it does fine here, too. It has a very fine texture like the Leavenworth’s Sedge, but it’s a much smaller plant. Six inches tall and maybe 12 inches in diameter. It likes the shade as most of the Carex do.

And the fruiting time in the spring is usually the best time to make an identification of some unknown sedge. In fact, unless they’re in bloom, it’s almost impossible to tell which sedge they are or what they are.

I had some good success with the germination of the seeds for the Texas Sedge. These seeds do provide sustenance to various birds and squirrels.

Here’s a good comparison of the three sedges that I’ve talked about. On the left is the Cherokee Sedge. The seed heads that hang down from the stem are still very evident even now. If you were concerned about the plant seeding around, you can readily edit the many seed heads. Plant in the far right is the Leavenworth’s Sedge, and you can note the width of the leaves, the difference. In the front is the diminutive Texas Sedge. This was one of a batch that I started from seeds this spring.

This one is Carex flacca or Blue Sedge. It’s also called Carex glauca. This is not a native sedge, but I really like it. And this, in 1771, a German botanist and zoologist discovered the plant. And since it was a new species, he named it Carex flacca. The following year, an Italian physician and naturalist described a plant he called Carex glauca because that word glauca means whitish or bluish covering. And you can see where he would have gotten that name. So, that name became accepted even though the ruling in effect was always that the first name for a given plant should prevail. They called it first in time rule.

I do like the color this gives in the garden. And it is spreading but it’s only, oh, maybe 10 inches tall, and it spreads very slowly.

Thank you.

[MUS—AND THAT’S IT]