By Mike Weilbacher, Executive Director
Autumn is notable for so many things: crisp weather, colorful trees, birds and butterflies migrating south, and my favorite sign of the season, fields overflowing with goldenrod and aster.
Yes, goldenrod, scourge of those hay fever commercials, the ones with some poor sneezing schmuck standing shoulder-deep in a field of stunning yellow goldenrod, waving the white flag of surrender. Trouble is, goldenrod doesn’t give you hay fever. Its pollen is too heavy, dense, sticky—we don’t breathe it.
But goldenrod unfortunately blooms at the same time as ragweed, a wind-pollinated nightmare that pumps trillions of pollen spores into the sky, praying one lands on another ragweed. Instead, it lands in your nose, and ACHOO! So ragweed is the culprit, its nondescript flowers allowing it to float under the radar screen—and goldenrod gets the bad press.
It’s a shame, because goldenrod just happens to be one of the most important plants of the seasonal year. As the growing season begins to wind down, insect life is at its peak—butterflies and bees, aphids and ants, the creatures that literally hold up ecosystems as the base of food chains, have had the entire spring and summer to go through multiple generations. Just as they are at their population’s peak, summer wildflowers begin winding down, and these insects need food for their last hurrah before winter.
Enter goldenrod. Like the wild version of the crocus evolved to be the sole source of nectar and pollen for Eurasian insects in the first moments of spring, goldenrod has evolved to take up the rear of the floral parade, among the very last wildflowers to bloom. So when you enter a goldenrod field in early fall, you will see the flowers literally abuzz with activity. Butterflies of all kinds will be nectaring on the flowers, including Monarchs heading south to Mexico. On a stop at Morris Arboretum in September to check out the goldenrod meadow, at least six butterfly species could be seen nectaring at one time, including two different kinds of swallowtails. A hummingbird moth, a beautiful butterfly cousin—a day-active moth that hovers over flowers like a hummingbird—trolled one corner of the meadow. Many beetles were crawling all over the floral heads to nibble on pollen grains, a great source of protein. Honeybees, bumblebees, flies of all kinds were working the blooms; spiders and praying mantises were stalking the other insects. Dragonflies cruised above the field, picking off any of the flying insects they could. Sparrows worked the field for seeds; kingbirds patrolled the edge for flying insects.
This is a goldenrod field at this time of year: a critical feeding station for literally thousands of species.
But it’s also the last chance café. Goldenrods and their other fall collaborators like asters and ironweeds will bloom deep into the autumn—and then the flower season is over. No more pollen; no more nectar. Oh, there will be seeds available for seedeaters in a meadow throughout the winter, and there are no shortage of seed-eating critters, but for butterflies and bees, this is it, their golden moment in the sun.
Goldenrods and their kin are especially adapted for this season. Insects are intensely cold-blooded (listen, for example, to katydids calling their name loudly at night in big three-syllable chirps; the frequency of their song is directly correlated to the temperature). As the days cool down, it becomes harder and harder for big-bodied bumblebees to work the field searching for pollen and nectar. So the goldenrods have compensated by evolving clustered floral bouquets, bunching their flowers closely together into groups, giving bees a target-rich energy-efficient pollen-collecting experience—a bee simply walks along a goldenrod stalk and encounters dozens and dozens of flowers. In turn, the bees oblige the goldenrod by making sure they are happily pollinated to produce next year’s seeds—a great exchange for both.
There’s even a fly that lays its egg in the stem of the goldenrod, chemicals in its ovipositor causing the stem to swell and grow an almost cancer-like ball. The fly’s larva sits inside that stem’s swelling ball, hiding during the cold winter while eating the walls of its home. But chickadees and downy woodpeckers have discovered this secret, and peck open goldenrod ball galls to get at the little maggot hiding inside.
There are six million stories in the goldenrod city. And none involve hay fever.
Happily, goldenrod has begun to rise in public opinion: I’ve seen it included in fall bouquets at flowers shops, and garden centers often include cultivars in their native plant sections. In your garden, it can be tall and it can take over, but it does extend your blooming season as late as Thanksgiving—not a bad run. And it is one critically life-saving plant in the fall season.
Just ask the nearest honeybee.
Mike leads a goldenrod workshop and field trip for Morris Arboretum on Saturday, October 19; visit morrisarboretum.org for more information. A version of this essay originally appeared in The Main Line Times.