In honor of today being Imbolc, an ancient Gaelic holiday celebrating the midpoint between the winter solstice and the vernal equinox (which has now been adopted by many neopagans and Wiccans), I wanted to showcase Senecio vulgaris (sometimes called common groundsel, chickenweed, simson, birdseed, or butterweed, although I prefer the name I first knew it by, old-man-in-the-spring), one of the very few plants that are flowering at this time of the year. It is considered to be an early bloomer by many, but I believe I’ve observed it flowering at our nearby cemetery in every month of the year.
Senecio vulgaris is a Eurasian native that has naturalized on every continent but Antarctica, though it is not particularly common in most tropical regions. This polyploid spreads quite easily and rapidly because it’s seeds have cottony pappus (somewhat similar to those of dandelions and other members of the family Asteraceae) that facilitate airborne dispersal with only mild winds. They are also readily self fertilizing, and can produce several generations per year, because they can go from germination to seed producing in about 5 weeks. It is said that a single plant can generate a million plants in a year if all generations are allowed to produce seed.
Though people are known to sometimes eat the leaves of this plant, that practice is not recommended, because all parts of this plant are toxic, containing up to 9 different pyrrolizidine alkaloids, many of which damage the liver and have a cumulative effect. It has been used medicinally by traditional herbalists to treat menstrual disorders, nose bleeds, stomach ailments (especially those involving parasitic worms), and as a diaphoretic (to induce perspiration), diuretic, and purgative, as well as a poultice for wounds, but internal use is not recommended for the reasons stated above. Most mammals avoid consuming Senecio vulgaris, although rabbits, goats, and sheep have been known to eat it.
This is the first of what will possibly be many profiles, during this late winter period, of plants considered by many to be weeds. But, as a recreational naturalist who doesn’t garden and lives in the middle of a city, I love weeds! They are often the only plants found growing wild in an urban setting, especially at the front and back ends of the growing seasons (which is, admittedly, one of the reasons they often outcompete the natives). For reasons I cannot entirely name, I am not particularly attracted to cultivated plants, although I do appreciate the beauty of other peoples gardens.
Still it is wild things that get my juices flowing and I find even the common weeds, especially in late winter when my eye hungers for color in the landscape, to be fascinating. And the main reason I can be fairly sure I’ve seen Senecio vulgaris blooming in every month of the year is because that tiny dot of yellow catches my eye amidst the browns and greys when all else seems dormant, and it thrills me to see it attempting to reproduce when there is so little sunshine and warmth.
Description– Small (up to 18” tall) annual with simple or branched stems, deeply serrated to pinnate, alternate leaves, and disk flowers that lack rays; leaves are mostly hairless, and the lower leaves have a petiole, while the upper leaves are sessile; flowers are small (5-10mm wide), yellow, mostly covered by 21 green involucral bracts which are 5-8mm tall and have black tips; stems are hollow, fleshy, and are green to purplish; seeds have a tuft of pappus that allows them to be dispersed by wind.
Similar species–Senecio sylvaticum has tiny ray flowers (usually less than 2mm long) and lacks the black tips on the involucre bracts; other Senecio have obvious ray flowers.
Habitat– Mesic disturbed ground in full to partial sun, up to 3,000’ elevation; seldom found in undisturbed, natural habitats, and prefers areas with low growth and scant competition
Range-Eurasian native that has naturalized almost worldwide; region wide in the PNW in appropriate habitat.
Reproductive timing-Flowers year around in mild climates, but primarily from February through October in our region; individual plants flower for 3-4 weeks; may bloom in as little as 5 weeks after germination.
Eaten by-One of only a few larval hosts for the moth Tyria jacobaeae, as well as Orthonama obstipata and Xestia c-nigrum; adults and larvae of the flea beetle Longitarsus jacobaeae feed on this plant, as do aphids in the genus Macrosiphum; rabbits sometimes eat this plantbut most mammals avoid it because of its toxicity; pine elfins and some lycaenid butterflies sometimes utilize the nectar, as do some syrphid flies and solitary bees; apparently some birds will eat the seeds.
Etymology of names– Senicio is reportedly from the Latin word for ‘old man/woman’, because the white pappus bristle resemble the white hair of the elderly. The specific epithet vulgaris is from the Latin word for ‘common’, for obvious reasons. The common name groundsel is from the Anglo-Saxon word ‘groundeswelge’, which means ‘ground swallower’, in reference to how quickly this plant spreads.
Senecio vulgaris (Birdseed, Chickenweed, Common Butterweed, Common Groundsel, Grimsel, Grinsel, Ground Gutton, Groundsel, Grundsel, Grundy Swallow, Old Man In the Spring, Old-Man-In-the-Spring, Ragwort, Simson) | North Carolina Extension Gardener Plant Toolbox