Wild Side: The inscrutable dandelion

Is it good for bees, or not?

A female Agapostemon virescens, a native generalist bee, forages on a dandelion in early May 2023. —Matt Pelikan

If there’s one point I truly insist on regarding natural history, it’s that the most common organisms and the most familiar settings can be every bit as interesting as the most exotic species and places. Amazing stuff sits right underfoot.

A good example comes from that most familiar of plants, the dandelion. With its coarsely toothed leaves, enthusiastic taproot, golden flowers, and delicate heads of parasol-bearing seeds, this plant is known to all.

But it’s hard to think of another plant that has inspired such a wide range of human responses, and even harder to think of one that is currently the center of so much discussion among plant enthusiasts.

At one extreme, the dandelion has been reviled as a pernicious weed. That was how I was introduced to it: a non-native species that doesn’t belong in the New World, and that I was paid a penny a stem to yank out of our front yard when I was a kid.

At the other extreme, the dandelion is idolized as a medicinal plant (based on an unfortunate childhood experiment, I can attest that older leaves, poorly prepared, will give your innards a salubrious scouring); a source of wine, made from the flowers; of passable coffee, made from the roasted taproot; and of healthy greens for the table, if you harvest young leaves and cook them in a couple of changes of water.

But a lot of what you think you know about dandelions is apparently not true. While I grew up knowing just one dandelion species, Taraxacum officinale, of European origin, botanists in Europe have proposed scores of species of dandelion. Many have made it to North America. A 2019 article in the journal Botany recounts the identification of more than 100 such species in the Canadian province of British Columbia, while also referring to native North American species found at high elevations and high latitudes.

The dandelion, that is to say, appears to be a vast complex of closely related forms, the sort of cluster of “microspecies” that calls into question the whole notion of what the word “species” refers to.

Its taxonomic peccadilloes aside, dandelions have seen their stock skyrocket in recent years as concern over the status of pollinators moved into mainstream awareness. “Leave the dandelions!” proclaim inescapable social media memes, insisting that this once reviled plant is a vital early season source of pollen and nectar for bees.

One does not, of course, look to internet memes for subtlety, and the pro-dandelion admonitions seem to me to reflect an interesting mix of truth, fiction, and selected values.

There’s no question that dandelions are among the first flowers to appear during a typical dismal Vineyard spring. And yes, bees do visit them. But my observations suggest that it is the Western honeybee, which evolved on the same continent as the dandelions that are now established in our region, that is most fond of these yellow flowers.

Enter my ambivalence about this bee, which exists as a sort of human-supported livestock on the Vineyard. They’re fascinating insects, useful pollinators for certain crops, the source of a truly delectable secretion — and, potentially, destructive competitors against native bee species. So whether the role dandelions play in supporting honeybees is beneficial or not depends on your perspective.

Among our native bees, there appears to be only a relatively small number of generalist species that visit dandelions in early spring (many native early season bees are closely tied to particular native flowers, such as willow or blueberry). While one might think that adding an early season food source would be beneficial for native bees, I don’t think that can simply be assumed.

First, do the nectar and pollen of dandelions truly meet the nutritional needs of these bees? Or are these flowers just junk food, perhaps distracting bees from finding the flowers they should be foraging on? I have no idea whatsoever. But the answer to that question has implications for whether dandelions truly are helpful for these insects.

Assuming dandelions do represent worthwhile food, adding an abundant, early-season flower could also exert unexpected effects on bee behavior and evolution. Living in North America for millennia before the introduction of dandelions, native bees somehow managed just fine, their life cycles coordinated with the bloom periods of their natural food sources.

Adding dandelions might reduce the penalty for individual bees that emerge very early in the season, altering over time the seasonality of native bee life cycles. And bee species would benefit unevenly from the new resource, potentially altering the species mix, which would in turn reshape the pollination services for plants. Are these changes, if they exist, good or bad? I doubt anyone can say.

Whatever the case, dandelions, in all their recently discovered taxonomic diversity, are here to stay. As with many ecological changes, the advent of this complex of species has likely had subtle but possibly pervasive effects on the native species that interact with it. The complexities surrounding this familiar plant highlight what it means to live in a world so heavily modified by human culture and commerce.