For the love of goldenrod

It's that time of year again where we must confront the truest bias out there -- anti-goldenrod propaganda!

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Why do plants have showy, beautiful flowers? Why is goldenrod honey so delicious and sought-after this time of year? The answer to both of these questions is simple: Pollinators LOVE nectar. It's full of good sugars that bees, butterflies, and hummingbirds depend on to live.

A beautiful flower is a big advertisement, shouting "HEY, WE'VE GOT NECTAR HERE!", and the shape of that flower can give you clues as to who they're targeting (flowers are the ultimate marketing pros). Long, tube-shaped flowers are probably meant for the long beaks of hummingbirds. Big flowers high in the trees might instead be meant for bats. And goldenrod, with its many small flowers clothed in bees' favorite color---those are meant for the bees.

Not all pollen is created equal. Many plants skip the costly production of showy flowers and nectar, instead producing pollen that is lightweight and meant to be carried far away on the wind. Because they don't rely on direct pollination, wind-pollinated plants have to produce a LOT of pollen to make sure that some of it reaches someone else's flowers or cones. This is the pollen that often causes seasonal allergies.

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Since goldenrod is insect-pollinated, it would make no sense for goldenrod to create pollen that is blown away in the wind before the bees can do their job. So who is the culprit?

Experts agree, it's likely ragweed*. Ragweed is an unassuming, wind-pollinated plant that blooms at the same time as goldenrod. Ragweed's flowers are all business, no show, and they fly under the radar while letting goldenrod take all the heat.

And, if you're allergic to ragweed, I've got bad news for you: As the climate warms, growing seasons get longer, including the allergy window for ragweed.

So, if you've always blamed goldenrod for your fall allergies -- maybe take a hard look in the mirror and ask yourself: Could it be ragweed?

Ragweed specimen I found on my walk the other day. Note the tiny flowers with no ads for insects.

​*Although there have been reports of contact dermatitis and rhinitis associated with the latex produced by goldenrod: Bains et al 2008.