Back from Extirpation: Swamp Sunflower

At our Lindsay Preserve in Warwick Township, there’s been a towering forb blooming at a time when most other plants are in the process of going dormant. They stand out (quite literally) above the other meadow dwellers, but whether they’re tall or small, the existence of Swamp Sunflower (Helianthus angustifolius) at this preserve, and Pennsylvania more generally, is particularly significant.

Swamp sunflower blooming at our Lindsay Preserve

Swamp Sunflower is listed as extirpated in Pennsylvania. Extirpated is a fancy ecological term which means “locally extinct.” “Locally” can vary from individual sites to entire countries and even continents. To contrast, the word “extinct” means a species does not exist anywhere in the world. In the northeast, Swamp Sunflower is mostly found along the coastal plain, most of which is heavily developed in Pennsylvania. The destruction of wet meadows and other coastal environments, in conjunction with the establishment of invasive species like Phragmites australis, likely led to their extirpation.

While its status in Pennsylvania has not been updated just yet, Swamp Sunflower appears to be establishing well at our largest preserve, and in a meadow where it was intentionally planted. Swamp Sunflower seeds were included in a seed mix that we used to convert a 15-acre agricultural field to a pollinator meadow. That project was initiated in the spring of 2025, and we’re already seeing conservation wins such as this as we conclude year 2. 

Our familiarity with this species is limited given how uncommon it is in Pennsylvania. However, we have been noticing dozens of hoverflies and small bees visiting their flowers, and we’ve also watched Monarchs visiting them for fuel as they make their long treks back to Mexico. 

A particularly happy swamp sunflower

Ecology aside, something we may not have anticipated is the satisfaction that’s felt when we come across particularly tall individuals. There’s something hopeful and encouraging about seeing a once extirpated species not only growing, but thriving in the place that you put it.  

I hope this article has sent some good spirits your way. If you’d like to support the reestablishment of this species and others, look into native plant nurseries near you. They may carry Swamp Sunflower and other uncommon species for that matter. And of course, support your local land trusts!

As always, thanks for reading.

-Sebastian Harris