Yellow Spring 3: Butterweed, Packera glabella.

Thursday, May 7, 2015

From early to late spring, the delta country is alive with fields of yellow.  There is a succession of species with yellow flowers, but there are habitat, floral, and temporal differences.  These characteristics are not always apparent to the novice, but a seasoned naturalist may easily identify the different species, even at 70 mph on the interstate!

As one of the earliest bloomers, Butterweed, Packera (syn. Senecio) glabella, often seems to be the only wildflower along the roadside.  Butterweed seeds germinate in late fall and winter.  By late winter, their wet habitat contains roseates of broad, dark green leaves with purple undersurfaces.  By February, flower stalks begin to rise and blossoming of yellow flowers soon follows.  This is often their best month, and the population gradually declines in the ensuing weeks.  Some, however, may persist into early summer, but they will not be the dominant species they are in February.

If you want to know Butterweed, you need to stop in a safe place and walk among the flowers.  Butterweed has a single 1-3 foot tall stalk that has obvious ribs (is not smooth), with clusters of flowers at the top.  Each flower has a central ball of disk florets with up to 15 narrow florets radiating out like sun rays.  They differ from the species that follows and exists sympatrically for some weeks, Hairy Buttercup, which has 5 petals and no central disk of florets.

Since Butterweed flowering coincides with pollen production of oaks and pines, people frequently associate the showy flowers with allergies.  Actually, Butterweed has relatively large, sticky pollen grains that are moved about by bees and other insects.  Oaks and pines, however, have wind blown pollen that, when inhaled, may cause illness.

The shear beauty of acres of Butterweed is neat in itself, but the story doesn’t stop there.  We often forget that plants compete with one another, just as animals do, and they must also develop survival and reproductive strategies.  Butterweed is very successful because it is one of the first bloomers, so when it is at its maximum growth and requires the largest amount of resources, there is little vegetative competition.  Also, since it is the first major bloomer after winter, it gets the bulk of attention from bee colonies that are beginning activity.  Judging from the density of stands of Butterweed, their niche seems to work.

But other than painting a yellow swath across the delta, does this glorious plant offer anything else?  It may well be the most economically important wildflower in Louisiana!  Butterweed tends to grow in low, rather moist areas such as ditches, swamps, and back-water places along bayous and rivers.  Take, for example, the Atchafalaya River basin.  Each spring, Butterweed covers the exposed floor of the basin.  Before the river begins its annual rise, bees visit and Butterweed completes its reproduction, sending its seeds flying into the breeze.  As the plants are covered by water, they die and decompose.  Enter the crawfish.  One of the most important functions of crawfish (off the platter, that is) is that they are detritivores, feeding mostly on non-living organic material.  Crawfish while away their days chewing up their food source, changing big leaves and stalks into either small pieces that float away into the water or into edible tissue.  Butterweed is the main entre on the menu, and without it our state would have a much smaller fishery of our Cajun’s “écrevisse.”

REMEMBER:  If you stop along highways to examine nature, be very careful about adjacent traffic. Not everyone is cautious about naturalists wandering along rights-of-ways.

The next time you take notice of any of our natural resources, ask “I wonder how it fits into the overall scheme of things?”

 

Butterweed, or Yellow Top, Packera glabella, are showy and wonderful spring flowers.  Photo from Wikipedia, May 7, 2015.

A Butterweed plant flowering in a roadside ditch.  Photo by Bob Thomas. 

This is a typical spring roadside view of Butterweed taken in Bridge City, La., on January 25, 2013. Photo by Bob Thomas.

The pre-flower, early growth is lovely. Photo by Bob Thomas.

A stand of Butterweed (larger flowers to the right) and Hairy Buttercup (smaller flowers to the left) in New Orleans City Park, taken on March 30, 2015.  Photo by Bob Thomas.