Butterweed, Packera glabella
Since Covid restrictions have lifted, crews have continued to mow and poison plants on the side of the Greenway’s main trail. Other crews have even attacked the growth around the electric towers that had done such a good job protecting wildflowers last year. All this mowing and poisoning has greatly reduced the amount of poison ivy growing on the side of the trail, which is a good thing. But it has also reduced the biodiversity of the plants found there. Even the violets, which had been so plentiful a few years back are making a very sad showing this season.
Mowed Greenway trail
Mother nature hasn’t helped the wildflowers either. The weather this year has been chaotic. In early March, for a day or so, temperatures reached into the mid 80’s only to plunge back down below freezing. This damaged a lot of buds. Since then, temps have consistently gone up and down from the 80s to the 40s and back again. That is why my latest featured wildflower, the Butterweed, became the star of the trail, standing out like the diva of the forest, flowering from late February and continuing to create a chorus of beautiful yellow flowers to this day!
I swear these bright yellow flowers topping the plants’ tall verdant stalks weren’t there last season because they are quite striking and couldn’t have been missed. Their current abundance is probably is due to all the mowing that occurred leaving empty patches of moist land just ready for airborne seeds to touch down and sprout on them. Butterweeds are annual plants, and members of the Aster family, which means that what we see as being one little flower is actually a composite flower made up of several disk flowers and up to 15 ray flowers on each tiny bloom. Each of these flowers will produce a seed. The composite flowers shut tight when busy producing fruit. Each seed is surrounded by fluffy floss similar to dandelion fuzz called “achenes” or pappus. When the seed tubes open, the wind catches the crown of hairs and propels each seed, dispersing them sometimes kilometers away. I was not able to find information about how far a Butterweed seed can travel, but it is documented that dandelion seeds, which are larger and heavier, can travel as far as 100 kilometers in the wind!
“Butterweed” is a popular name for plants. Canadians use the word for a different plant with the scientific name of “Erigeon canadensis”, or “Conyza canadensis”. In the 17th century this plant was brought to Europe and has now spread to most of the temperate zones of Asia, Europe and Australia. In English it is also called Canadian Fleabane, Horseweed, or Mare’s Tail. This plant emerges in the late spring, and is nowhere near as pretty as the one found on our continent. Oddly enough, however, some Packera glabella plants can be found in a very limited area in Northern France near La Manche, or the English Channel, in Normandy.
The Butterweed plant I am describing is Packera glabella also called Cress-leaf Groundsel, and Yellowtop. It is native to southeastern and central United States growing from Florida to Texas, and north to Illinois and the southern part of Lake Michigan. The Packera glabella plant has not been able to cross the Rocky Mountains, and seems to have had a difficult time even crossing the Mississippi river and the Great Lakes.
It is difficult to recognize a Butterweed plant until it starts to flower. The leaves emerge in the fall and grow as a rosette with leaves opposite on the stem. The hollow stems will eventually grow to reach up to 28 inches tall, and are hairless and often unbranched. A large cluster of flowers will top each stem. The leaves are interesting. They are deeply divided in rounded segments, or lobes, but get smaller in size as they reach the top of the plant. As the plant ages, the stem supposedly becomes ribbed with red or purple streaks and the leaf arrangement becomes alternate. The plant forms large colonies in suitable habitats, which means in moist to wet land. Although it is an annual, each plant will drop so many seeds that it may appear to be a perennial. It will bloom in either sun or shade, but the one requirement is that the site is moist. In North Carolina the plant was first noticed on the southern and central outer coastal plain, but in recent decades it has moved westward and further inland, attracted to brown-water swamps, bottomlands and wet forests in the lower Piedmont area. The name “Piedmont” is what geologist call the plateau between the Coastal Plain or the Sand Hills and the Mountain regions of Eastern or Western United States. The elevation of the Piedmont is relatively low, from 300 feet to 1,500 feet near the base of the mountains. Lack of moist ground at higher altitudes might be a factor contributing to where and how this wildflower spreads.
Butterweed can become a pest if it infects a livestock pasture. Like onions, the plant produces the alkaloid pyrrolizidine. But butterweed produces so much of this chemical that eating a lot of it will cause veno-occulsive disease which will clog up small veins in the liver causing fluid retention. Larger amounts of the stuff will cause acute symptoms, destroy the liver and kill livestock, wild animals, humans and birds. Butterweed looks like it should be edible because it looks so much like wild mustard and wild radish, two edible plants, but in lab tests it is best used for poisoning rats. Yet while the plant is avoided even by rabbits and deer, its nectar and pollen are sought by a variety of bees, flies, beetles and other insects. One bug, the Seed Bug, even stores the toxic chemical from this plant in its body to use as protection against its predators!
Butterweed is not without its benefits, however. It grows in the winter and has pretty flowers that have a lovely aroma (although I had to get very close to a flower cluster to appreciate it.) Growing on the side of a river or stream, Butterweed will stabilize banks against erosion. And the thick growth of a colony of Butterweed provides cover for animals, insects and birds that visit the stream for water or to hunt for food.
Butterweed used to be classified as being in the Senecio genus along with ragworts and succulent plants, but it is now classified as being in the Packera genus, a name that honors botanist John G. Packer (1929-2019) who was born and raised in England but studied and taught at the University of Alberta in Edmonton, Canada. Packera is a genus of about 75 daisy-like plants that have the same number of chromosomes as Butterweed. Its species name, glabella refers to the glabrous, or smooth and not hairy surface of the plant’s leaves.
As usual, I have found references that say that Native Americans used this plant as a medicine to help cure various ailments among them menstrual problems and abdominal cramps. But I doubt that this is true. There are so many other native plants that help with stomach and menstrual distress that I’m sure Native people would have noticed how toxic Butterweed is and tried hard to avoid ingesting it.
Want to see a cool map of where this plant can be found? Go to this link:
https://identify.plantnet.org/canada/species/Packera%20glabella%20(Poir.)%20C.%20Jeffrey/data
Want to learn more about this invasive, but beautiful plant? Check out the references below:
Arlene Marturano, “Golden Beams of Bad and Beautiful Butterweed” Columbia Star, May 11,2018, https://www.thecolumbiastar.com/articles/golden-beams-of-bad-and-beautiful-butterweed/
B.A. Sellers, Devkota, P. et al., “Cressleaf Groundsel (Butterweed) Identification and Management in Pastures”, Askifas, University of Florida, https://edis.ifas.ufl.edu/publication/AG406
Lady Bird Johnson Wildflower Center, the University of Texas at Austin, Plant Database, “Packera glabella”, https://www.wildflower.org/plants/result.php?id_plant=pagl17
Green Deane, Eat the Weeds, “Common Non-Edible Plants”, and “Pyrrolizidine on my Mind” https://www.eattheweeds.com/ufos-2/#:~:text=Leave%20it%20alone.-,NOT%20EDIBLE.,that%20can%20damage%20your%20liver.and https://www.eattheweeds.com/pyrrolizidine-on-my-mind/
Missouri Department of conservation, “Butterweed”, https://mdc.mo.gov/discover-nature/field-guide/butterweed
C. Jeffrey, Vascular Plants of North Carolina, https://auth1.dpr.ncparks.gov/flora/species_account.php?id=576#:~:text=Butterweed%20is%20readily%20identified%20by,Packera%20species%20in%20the%20state.