What welcomes loads of visitors, looks good doing it and doesn’t make you sneeze?

Every August, when the goldenrods started flowering in upstate New York, we knew that winter wasn’t far away. Their deep-yellow blooms brightened fields and roadsides, providing nectar for a variety of late-summer insects, including Monarch butterflies migrating south.

Goldenrods (Solidago spp.) are mostly native to North America, and overall there are some 100-120 species. South Carolina has about 28 different kinds, and here, too, they signal the end of hot weather and the beginning of fall.

Although often blamed for “hay fever,” goldenrods are insect-pollinated and their heavy, sticky pollen does not actually cause allergies.

The real culprits are ragweeds (Artemisia spp.), less conspicuous plants that grow in similar habitats and bloom around the same time. A single ragweed plant can release a billion light-weight pollen grains that are easily spread by the wind and serve as a major cause of allergic rhinitis in the fall.

Like ragweeds, goldenrods are closely related to daisies, sunflowers, and other members of the aster family. Look closely at a blooming stem of goldenrod and you’ll see clusters of many flower heads, each looking like a miniscule daisy. A single “daisy” itself comprises still tinier flowers: “disc” florets, clustered in the very center, and thin “ray” florets radiating out in a circle around them.

Goldenrod patches are fascinating microcosms of their own, providing food and habitat for a diverse assemblage of animals.

Many species of butterflies, bees, beetles, wasps, and flies act as pollinators while foraging for goldenrod nectar. The caterpillars of certain small moths feed on goldenrod leaves. And crab spiders, praying mantises, anoles, and other predators prey on all of the above.

There’s even a tiny fly (Eurosta solidaginis) that lays its eggs on goldenrod stems. The newly hatched larvae (maggots) burrow inside the plant, feeding as they go. Their presence induces the plant tissues to grow abnormally, producing bulbous structures (galls), each containing a tiny, legless, developing gall fly.

These galls attract chickadees and woodpeckers, which peck them apart and eat the larvae inside. Also, parasitoid wasps lay eggs inside the maggots, appropriating them as food for their own offspring.

The complex relationships between goldenrods and their many visitors and residents have provided biologists with fertile opportunities for research.

And despite their invasiveness, goldenrods have become popular garden plants because of their showy blooms and attractiveness to butterflies and other pollinators.

Several states have even singled out goldenrods for special recognition. Tall goldenrod (Solidago altissima), for example, is the state wildflower of South Carolina.

This story was originally published October 2, 2017 at 8:41 AM with the headline "What welcomes loads of visitors, looks good doing it and doesn’t make you sneeze?."