From early to late spring, the delta country is alive with fields of yellow. As one of the earliest bloomers, yellow-top, or butterweed, (Senecio glabellus) often seems to be the only wildflower along the countryside. Yellow-top seeds germinate in late fall and winter. By late winter, their habitat contains roseates of broad, dark green leaves with purple undersurfaces. By February, flower stalks begin to rise and blossoming soon follows.
Since yellow-top flowering coincides with pollen production of oaks and pines, people frequently associate the showy flowers with hay fever. Actually, yellow-top have 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 yellow-top 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. Yellow-top 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 yellow-top, their niche seems to work.
But other than painting a yellow swath across the delta, does this glorius plant offer anything else? It may well be the most economically important wildflower in Louisiana! Yellow-top 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, yellow-top covers the exposed floor of the basin. Before the river begins its annual rise, the bees visit and yellow-top 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. Yellow-top is the main entre on the menu, and without it our state would have a much smaller fishery of of our Cajun’s “ecrevisse”.
The next time you take notice of any of our natural resources, ask “I wonder how it fits into the overall scheme of things?”