Close-up of the flower of Tradescantia occidentalis
Tradescantia occidentalis, or prairie spiderwort, is a perennial monocot found in central North America. Although it has a fairly widespread distribution, there are only four known populations of this species in Canada, where it is listed as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Prairie spiderwort grows in grasslands and on partially-stabilized sand dunes. In Canada, suitable habitat occurs only in the southern parts of the prairie provinces: Alberta, Saskatchewan, and Manitoba.
Tradescantia occidentalis has semi-succulent stems and narrow-bladed leaves. The 3-petaled flowers grow in a raceme of up to 10 flowers, which can be pink, white, violet, or most commonly, dark blue as shown in today’s photo. The bright yellow anthers contrast beautifully with the deep blue of the petals and the blue-hair decorated filaments. Some sources claim that the spider-like appearance of these hairy filaments give spiderwort its common name, while others attribute the name to cobweb-like strands that form from a sticky fluid when the leaves or stem are broken.
The habitat required by Tradescantia occidentalis (PDF) is quite specific. Sand dunes must be fairly stable, yet also must have some bare patches where seedlings can become established, as prairie spiderwort only reproduces by seed. Historically, regular fires and disturbance by ungulates routinely created patches of bare sand for Tradescantia occidentalis to colonize. Now, Canadian management plans call for rangeland management practices and prescribed fire to create the levels of disturbance needed by this species.
You may be wondering, if population levels of Tradescantia occidentalis are healthy through most of its range, why worry about a few small populations in Canada? A report by David Fraser, titled Species at the Edge: The Case for Listing of “Peripheral” Species (PDF), does a good job of explaining some of the principles that guide ecologist’s concern for peripheral populations. One of the numerous arguments presented by Fraser is that individuals growing in marginal habitats are exposed to higher selective pressures, and are usually genetically distinct from core populations. This genetic diversity may prove to be an important factor in the long-term survival of a species.
What beauty and intense color to come across on a sand dune or prairie…
On the other hand, the sand dunes along the beaches of the Carolinas have worker plants — sea oats [Uniola paniculata]. It’s illegal to mess with sea oats in any way considering their important job of sand stabilization. We couldn’t make it through a tropical storm or hurricane without them.
I belong to a community garden in New York City and every year our plots are invaded by Tradescantia occidentalis (same color as shown above) and Houttuynia cordata. If anyone in Canada or elsewhere would accept them, we’d be happy to send the plants along. No matter how deep we dig and root them out, they proliferate. I certainly never planted any in my plot and we don’t know how they arrived.
Are my eyes playing tricks on me? The photo looks 3D!!! This is fairly invasive in my area, but aside from that- what kind of camera or techniques did you use to get this picture looking the way it does? Did you use stacking???
Rick
We use Tradescantia stamen hairs in our Botany labs to demonstrate cytoplasmic streaming. The hair cells look gorgeous under the light microscope, with softly spiralling cell wall striations and vigorous cytoplasmic streaming around a large central vacuole. It’s always hit and miss if our plants are flowering on the day of a lab, but when they do it’s appreciated by everyone. I’ve never seen Tradescantia in a natural habitat. That would be a real treat to see.
Toinnette, is it possible what you think is tradescantia is actually asiatic dayflower, Commelina communis? I am from NYC too and I know that’s a very common blue flowering urban weed that I used to think was a tradescantia.
Tradescantia gres in my backyard in New Orleans. They were not that aggressive so I did not pull them out. I love blue in flowers.
BTW, some popular names are so off-putting such as Spiderwort or Lousewort. Does anyone know how these names originated?
“cobweb-like strands that form from a sticky fluid when the leaves or stem are broken.”
T. virginiana has this feature too, earning it (esp among boy campers) the common name “snot weed.”
We have Asiatic Dayflower too, but that’s easily pulled up. No deep roots. It’s the spiderwort that is truly invasive and impossible to tame.
From Wikipedia To Lize Choi:
“According to the Oxford English Dictionary’s Ask Oxford site, “A word with the suffix -wort is often very old. The Old English word was wyrt, from Proto-Indo-European origins that connect it to root. It was often used in the names of herbs and plants that had medicinal uses, the first part of the word denoting the complaint against which it might be specially efficacious…By the middle of the 17th-century -wort was beginning to fade from everyday use.[1]
The Naturalist Newsletter states, “Wort derives from the Old English wyrt, which simply meant plant. The word goes back even further, to the common ancestor of English and German, to the Germanic wurtiz. Wurtiz also evolved into the modern German word Wurzel, meaning root.”[2]
What a great collection of comments! Wish I’d taken _your_ botany course, Caroline!
The Tradescantia I see most commonly is grown in a hanging basket and tumbles strings of widely spaced child plants (etiolated stems in dim light?) over the sides of the basket, for several feet if the basket is high enough. This variety is light green and white with long narrow lanceolate leaves and the descending plantlets look quite like spiders climbing down a web strand. I’ve always thought that was why the name.
The tiny Spotted Spurge that is so often included in the pots of nursery plants or pops up in bare spots was always known to me as WartWort. The irritating milky juice was presumably able to make warts go away. But I looked for Lousewort which I always thought was something to do with the flowers which could remind one of a creature — especially the snouted ones– and Wikipedia says that it used to be thought that it caused the lice found on livestock grazing among it. Which makes me wonder if overgrazing encourages the host plants — and stresses the livestock, making them more susceptible to massive louse infestations. (The US Forest Service cagily says “There seems to be little evidence to support this claim (that lousewort causes louse infestations).” “Little?” Not “no?”
I’m unclear. Is this an extralimital population, or is it a clear introduction to Utah as an adventive, naturalized, or cultivated occurrence?
No, it is native, see Tradescantia occidentalis. I know the write-up is more about Canadian populations, but it is extensively distributed through the central USA and adjacent areas.
There are other Tradescantias more likely to be seen as “weeds” in NY state. Tradescantia virginiana is in many counties, including around NYC. Same with T. ohiensis. Tradescantia occidentalis is found outside of gardens only in Albany county per the NY Flora Atlas -http://newyork.plantatlas.usf.edu/Default.aspx)
None are native in NY state, and they all look pretty similar, so I think it would be hard to tell which you have unless you do a good keying out. I have grown T. ohiensis and T. virginiana in my meadow garden, and love them both. (Never tried pulling them out.) Note that all 3 of these are fairly erect plants, although they can fall over when in flower.