September, the golden month on Cape Cod. Sunrises and sets that fill the mind’s eye with color and light. Goldenrod blooms across dunes and meadows, roadsides and gardens. Solidago sempervirens, Seaside Goldenrod, is just beginning to open at First Encounter Beach. A walk at Fort Hill in Eastham reveals multiple species in flower, like yellow fireworks that fell from the sky. 

There are eleven species of Solidago on Cape Cod, all bursting with bright golden yellow flowers throughout late summer into fall, save one: Silverod - Solidago bicolor. These tiny flowers are white, crowded on long stalks with deep green leaves that travel up the entire length of the stem. Yet for the most part, members of this species are hard to discern from one another; leaves, scent, and habitat can lead to clues. 

Translated from Latin, Solidago means, ‘to make whole’, as it was used for multiple ailments in traditional medicine. Indigenous Americans used it as a remedy for toothache, fever and cough, as well as a dye plant to create shades of yellow. Natural dyers still work with this plant today. 

Goldenrod is often confused with ragweed, a similar looking plant with airborne pollen. Yet, Solidago’s pollen is sticky and heavy. Bees, wasps, and butterflies visit often, collecting nectar from the plant’s many flowers. Goldenrod’s late blooming season offers fodder for beneficial pollinators before winter hibernation.

This herbaceous perennial thrives in a variety of habitats across our landscape, blooming once the days turn shorter and nights get longer. Also called photoperiodism, this response from both plants and animals is due to the amount of night sky they’re exposed to; goldenrod blooms only after a continued period of darkness. 

Solidago’s reign over the landscape this time of year is a sign of fall to come, summer made whole. This reliability is an assurance, golden flowers signaling a transformation in the season. Nights stretch out and lengthen. The sun begins to dip lower in the sky. 

As the month moves closer to the equinox, yellow flowers fade to a dull ochre fire, seed carried off by the wind. Rhizomes have spread underground. Next spring, these newcomers will grow inconspicuously throughout the landscape until the long, dark nights settle in, once again calling forth a beautiful riot of golden flowers.