We are already a good two or three weeks into spring here in southern New England, and like most springs, the weather has swung widely back and forth between frost and snow and warm weather, so warm, in fact, that on one 75 degree day my younger son went swimming in the lake with his friends (my older son thought they were crazy and did not get in the icy cold water).
Red osier stems which stood out so surprisingly in March are now completely drowned out by a new color exploding from the background of browns, subtle new-leaf greens, and touches of tree-flower reds. That color is YELLOW! Yes, the forsythia have bloomed and now dominate yards, gardens and roadways. Daffodils pop up like easter eggs in yards and wooded areas. A number of our local trees also make smaller, less showy flowers that are nonetheless bright dots of yellow among the branches. We are even starting to see the yellow of dandelion flowers blooming among the grass.
Forsythia, daffodils and dandelions are risk-taking plants, opening their flowers at a time when snow and frost are still possible in our forecast. But only one sturdy plant dares to open its yellow flowers when packed snowdrifts still sit in shady areas and any rare warm day is quickly followed by frosts and snow flurries. That bright and brave plant is coltsfoot.
I noticed coltsfoot for the first time one spring six or seven years ago while waiting for the school bus with my son (the older one – the younger was still a baby then). We met the bus where our smaller road met the ‘main’ (also small) road the that was on the bus’s daily route. To avoid traffic turning onto our road we would stand on the pile of gravel and old melting snow pushed up by snowplows next to the rough drainage ditch collecting runoff from the main road.
This wet gravelly area eventually is overgrown each summer with weeds … and poison ivy… and with a good population of mosquitoes, but on this early spring morning it was still bare except for a patch of bright yellow flowers that looked like tall thin dandelion blooms growing straight out of a pile of gravel, with no leaves in sight. I was mystified. Each trip to the bus stop, I would take a look at these lonely flowers poking out of the rocks, and the more I looked, the more I was sure they definitely were not dandelions. Where the stems of a dandelion flower are rather wide and smooth, these stems are thin and scaly, with little leaflike flaps held tight to the whole length of the stem.
And while the flowers did turn into white puffballs of seeds like dandelions, I noticed the seed heads looked different, bright white and a downy looking. One morning after seeing my son onto the bus, I picked one of these flowers and tried to blow off the seeds while walking home. Tried and failed…even pulling with my fingers didn’t dislodge them well. Those bright yellow flowers and white fluffy seed heads disappeared pretty quickly, but as the weather warmed, wide dark green leaves started emerging from that same pile of gravel.
These small observations built up over two or three months, but I didn’t really think much about them until those extremely un-dandelion leaves appeared. At that point pulled a dusty wildflower book pulled off my bookshelf, and finally discovered that the plants were in fact coltsfoot (Tussilago farfara)
For the last six or so years the appearance of those bright yellow flowers has marked for me that uncertain boundary between winter and spring, when temperatures swing wildly between summer-warm and winter-cold. But even though I religiously watch for coltsfoot flowers to emerge from the piles of dirt and gravel left behind by winter’s snowplows, I don’t actually know much about the plant. I vaguely assumed it was a native wildflower that I’d never really noticed before, but I never really considered the history of the plant itself.
Coltsfoot, some of you might know, is used in a number of different folk medicines. I had heard about this myself, and assumed those medicines were used by Native Americans because I was seeing the plant in the U.S. But when I started reading for this blog post, I learned coltsfoot is actually native to Europe and Asia, and is an ingredient in a number of different Traditional Chinese Medicines, where the flower is named kuǎn dōng huā. I tried to find a literal translation of that name to English, but failed. TCM (traditional Chinese medicines) uses coltsfoot flowers to treat cough and wheezing.
I also learned coltsfoot’s ability to treat cough is so well know that its scientific name, “Tussilago”, comes from the Latin words for “cough” (tussis) and ”to act on” (ago). Coltsfoot is also used in folk medicine in the northern Middle East (Turkey, Georgia) and throughout Europe, again to treat respiratory ailments. Apparently the plant was so well known for its medical uses that images of it were painted on the doorways of apothecaries in Paris (links to a book published in 1897 on ‘herbal simples’ of Europe). In fact, Pliny the Elder described the use of coltsfoot in his History Naturalis (AD 77) and Hildegard von Bingen also suggested its use in her Physica, written around AD 1150 (click here for source and primary references).
For more information about coltsfoot, where coltsfoot is found, how it grows, its pollinators, etc, follow this link to a wonderfully detailed entry provided the USDA and U.S. Forest Service.
Coltsfoot was probably brought to North America by colonists the same way a traveler today might pack a small bottle of NyQuil in their suitcase. But the plant quickly escaped kitchen gardens due to its amazing affinity for ‘marginal’ (difficult to grow in) and disturbed habitats. In fact, the very characteristics that made me notice coltsfoot in the first place (growing in gravel) should have alerted my ecology ‘spidey-sense’ that the plant was not native to the U.S. Invasives of any kind (plant, fungal, animal) often have a knack for moving in to really poor and disturbed habitats. In their native range, this ability to live on the margins gives them access to space and resources that would be greedily snatched up in a more stable and generally more favorable habitat. Once introduced to a new location, the same traits allow these tenacious organisms to move in to similar disturbed and marginal spaces in their new home. Coltsfoot is known to be a very aggressive plant even in its home range, where it easily escapes gardens and can quickly overgrow tilled soils on farms. Coltsfoot is now a common plant in eastern Eastern North America as well as the Pacific Northwest.
(Wikipedia has quite a good entry on invasive species and how species invasions can happen).
What is it about coltsfoot that makes it so commonly used in herbal medicines? Imagine life as a plant … plants don’t move (much), don’t bite, don’t fight for food or defend territory… or do they? Plants are actually extraordinarily competitive. But instead of defending their resources with behaviors and actions, they do it with chemicals. Every plant makes an entire arsenal of chemical compounds to protect itself from infection, deter animals from eating it, and damage or deflect other plants trying to use the same resources. These ‘secondary metabolites’ or ‘phytochemicals’ are biologically active compounds, meaning they can affect or impact the functioning of other living organisms. Because all living organisms share a surprising amount of cellular machinery, any compound that affects one type of organism (a caterpillar or a pathogenic fungus) may also affect non-target organisms (such as humans).
Coltsfoot contains many bioactive chemicals, including phenolics, flavonoids, sesquiterpenes, chromones, and pyrrolizidine alkaloids. For a very complete chemical analysis of the plant’s contents and how they apply to its ethnobotanical use, please see this article published just last month in the Journal of Ethnopharmacology. For those who don’t want to wade through a scientific research article, here is an overall summary of why coltsfoot has so very many medicinal uses (and also see this source).
Laboratory experiments using preparations of coltsfoot and specific chemicals isolated from it suggest its phytochemicals have the following wide range of medicinal qualities:
- anti-inflammatory (one or more of the sesquiterpenoids)
- immuno-stimulating (unidentified polysaccharides)
- anti-cancer (multiple compounds)
- anti-microbial/viral/fungal (weak to moderate activity, active compounds not yet identified)
- anti-diabetic/anti-obesity (caffeoylquinic acid, chlorogenic acid, rosmarinic acid)
- cardiovascular (stimulant, compounds not yet identified)
- neuro-protective (chemical compounds not yet identified)
- anti-oxidant (phenolic acid, quercetin-glycosides, assorted polysaccharides)
- cytoprotective (helps cells endure stress, compounds not yet identified)
The list above is truly impressive, but please, please take it with a huge grain of salt. The above qualities of coltsfoot were tested in lab experiments in cell cultures or in lab mice. One thing all biologists know is that just because something works in a test tube (or petri dish), that is no guarantee it will have the same effects in a human. In fact, many compounds that have interesting qualities in the lab turn out to be completely ineffective or even quite toxic for people. Coltsfoot can cause liver damage if taken at higher levels and/or for extended periods of time, and has been linked to at least one case of deep vein thrombosis and pulmonary embolism. The FDA lists it in its “Poisonous Plants Database” as likely unsafe to use, especially for those with allergy to ragweed, high blood pressure, heart disease, liver disease, or who are pregnant or breast-feeding.
My affection for coltsfoot that began when I first noticed ‘those weird dandelions’ six years ago has only grown since. I love that it is one of the very first plants to flower each spring, blooming even when we still have patches of snow in the shade. I love that it grows in the most unlovely of places, even in places that have collected an entire season’s worth of winter road salt. I love how bright it is, and how weird (the leaves emerge weeks after the flowers disappear!) After writing this post, I have an even greater appreciation for its shared history of humans, its veritable weapons cache of phytochemicals, and its ability to invade new habitats territory. A tough little plant indeed!