Category Archives: Prairie Plants

Ragwort – Prettier (and More Valuable) than its Name Might Suggest

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One of my favorite spring flowers is prairie ragwort (Senecio plattensis, aka Packera plattensis).  Its bright yellow flowers add welcome color to prairies every May, especially when it appears in high numbers.  We always try to harvest as much seed from the species as we can when we’re doing prairie restoration projects – partly because it fills some important ecological roles, and partly because I just like it.

Prairie ragwort along one of the hiking trails at The Nature Conservancy's Platte River Prairies, Nebraska.

Prairie ragwort was blooming along our hiking trails last week.  The Nature Conservancy’s Platte River Prairies, Nebraska.

Ragwort is typically a biennial, so it germinates and forms a rosette (a few basal leaves) its first season, then blooms and dies the next year.  I’ve read that the rosettes can survive more than one year before blooming, but I’ve never watched closely enough to confirm that at our sites.  Regardless, it’s one of a suite of opportunistic plants that can take advantage of open space created by drought, fire, and/or grazing.  I have a soft spot in my heart for those species because their presence and abundance helps me read what’s happening in our prairies.  When I see lots of ragwort and other opportunistic species in our sites, it tells me that the vigor of dominant grasses has been suppressed (because of weather, management, or both).  Suppressing dominant grasses is a major focus of our management work because that suppression facilitates the establishment and spread of many other plant species, not all of which are “weedy”.  While a number of opportunistic species (ragweeds, annual grasses, and many others) can indicate grass suppression, ragwort is nice because it also happens to be attractive – and because it flowers at a time of year when few other showy plants are blooming.

An eastern-tailed blue butterfly on ragwort at the Helzer family prairie by Stockham, Nebraska.

This eastern-tailed blue butterfly was feeding on ragwort at the Helzer family prairie a couple weeks ago.  Near Stockham, Nebraska.

A sweat bee on ragwort at the Helzer family prairie.

A sweat bee on ragwort at the Helzer family prairie.

Prairie ragwort attracts a large number of pollinators, including bees, flies, moths, and butterflies.  It is an equal opportunity resource for pollinators because it doesn’t hide or restrict access to its pollen or nectar with funny shaped flowers that require long tongues or other specialized body parts.  Everything is right there – available to any insect that lands on it.  In years like this one, when ragwort appears in big numbers, it might be the most important species available to pollinators during its blooming period.

I enjoy watching the ebb and flow of ragwort populations in response to our management, but I also like to monitor its establishment and spread in our restored (reconstructed) prairies.  Although its seedhead is fluffy like a dandelion, and the individual seeds can travel long distances, most end up falling near the parent plant.  As a result, new populations tend to radiate outward from the initial colonizing individual, and the size of ragwort patches can be an indication of the age of a restored prairie.  However, that pattern falls apart when a prairie isn’t managed with frequent disturbances because the populations can quickly shrink during years when thatch and vigorous grasses prevent seed germination and establishment.

A common checkered skipper butterfly feeds on ragwort in one of our restored Platte River Prairies.

A common checkered skipper butterfly feeds on ragwort in one of our restored Platte River Prairies last week.  The short heights of the grasses surrounding the ragwort plants in this photo are a result of both drought and grazing last year.

Ragwort is certainly not a rare plant in Nebraska, or one that is of conservation concern.  The droughty nature of our state helps keep populations strong, as does the prevalance of grazing in many prairies.  However, I think it’s important not to judge the value of plants by whether or not they are rare.  Ragwort, along with hoary vervain (Verbena stricta), common and show milkweeds (Aclepias syriaca and A. speciosa), and many other “weedy” wildflower species serve as great indicators of ecological events, step up to fill holes in weakened plant communities, and are among the more important wildflowers for pollinators in our prairies.

What’s not to like?

Photo of the Week – May 31, 2013

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I started my annual plant community monitoring this week.  That work consists mainly of inventorying the plant species within small sampling plots.  Forcing myself to walk regularly spaced transects and stare at a square meter of prairie at a time is a great way to find creatures and sights I might miss if I was just wandering aimlessly.  This week, for example, I scared up a couple jackrabbits and found a quail nest within a few minutes of each other, and found a number of pretty neat insects.  But in that particular prairie, the star of the show was Tradescantia bracteata (bracted spiderwort), which was scattered across the site in patches about the size of a small car.

A close-up look at a patch of bracted spiderwort, with prairie ragwort (Senecio plattensis) in the background. The Nature Conservancy's Platte River Prairies, Nebraska.

A close-up look at a patch of bracted spiderwort, with prairie ragwort (Senecio plattensis) in the background. The Nature Conservancy’s Platte River Prairies, Nebraska.  You can click on the photo to see a larger and sharper version.

These spiderworts were blooming in a prairie we planted back in 2000.  It has become of our most colorful sites – loaded with wildflowers of all kinds.  I didn’t see much spiderwort during the first 5-7  years of the prairie’s establishment (most of which were drought years).  Eventually, I started finding a lone plant here and there.  Those scattered plants have now formed colonies that radiate outward every year.

If you look closely, you can see that several of the spiderwort plants in this photo have been grazed.  They are blooming in a burned portion of the prairie, which is where cattle are focusing most of their attention (within our patch-burn grazing system).  Cattle really like to eat spiderwort, so grazing will probably impact the 2013 growth and seed production of the plants in this photo.  However, we just finished building a temporary electric fence to exclude cattle from about half of this same prairie for the rest of this growing season, so all the spiderwort patches in that exclosure should have a good year.  Next year, the patch of flowers pictured here will get a break from grazing too.

Although grazing can keep spiderwort plants short and decrease seed production, most of this species’ reproduction happens through rhizomes (underground stems), so annual seed production is not critical for its survival or spread.  In addition, periodic grazing helps open up space among the grasses and provides opportunities for spiderwort to continue its spread.  In fact, areas of our prairies that get little or no grazing tend to have fewer and smaller patches of spiderwort (though the individual plants often grow taller).