Bigelow’s Thoroughwort: A Rare Native Wildflower Worth Protecting
Meet Bigelow’s thoroughwort (Chromolaena bigelovii), a lesser-known native wildflower that’s as elusive as it is intriguing. This perennial forb belongs to the aster family and represents one of those botanical treasures that most gardeners have never heard of – and for good reason. It’s quite rare and has a very limited natural range.
What Makes This Plant Special?
Bigelow’s thoroughwort is a native perennial forb, meaning it’s an herbaceous plant that lacks woody stems and dies back to the ground each winter, returning from its root system the following spring. As a member of the Chromolaena genus, it’s related to other thoroughworts and mistflowers, plants known for their clusters of small, fluffy flowers that pollinators absolutely adore.
You might also see this plant listed under its older scientific name, Eupatorium bigelovii, as botanical naming can sometimes shift as scientists learn more about plant relationships.
Where Does It Grow?
Here’s where things get interesting – and a bit concerning. Bigelow’s thoroughwort has an extremely limited natural range, found only in Arizona and Texas. This restricted distribution makes it quite special, but also vulnerable.
- Species observed
- No observations
A Conservation Concern
Before you get excited about adding this plant to your garden, there’s something important to know. Bigelow’s thoroughwort has a Global Conservation Status of S2?, which essentially means its conservation status is undefined but potentially of concern. This uncertainty, combined with its limited range, suggests this might be a plant that’s struggling in the wild.
If you’re passionate about native plants and happen to live in Arizona or Texas where this species naturally occurs, you should only consider growing it if you can source it from reputable native plant nurseries that propagate their own stock rather than wild-collecting. Never collect plants from the wild, especially rare ones like this.
Growing Bigelow’s Thoroughwort
Unfortunately, detailed cultivation information for this specific species is scarce, which isn’t surprising given its rarity. However, we can make some educated guesses based on its botanical family and native habitat:
- As a forb native to the Southwest, it likely prefers well-drained soils
- It probably tolerates drought conditions once established
- Full sun to partial shade would be appropriate for most Chromolaena species
- Being a perennial, it should return each year from its root system
Better Alternatives for Most Gardeners
Unless you’re in Arizona or Texas and have access to responsibly sourced plants, you’re probably better off choosing other native thoroughworts or mistflowers that are more readily available and better suited to cultivation. Consider these alternatives:
- Wild bergamot (Monarda species) for similar pollinator appeal
- Native asters for late-season blooms
- Local Eupatorium species if available in your region
The Bottom Line
Bigelow’s thoroughwort represents the fascinating but fragile side of our native plant heritage. While it’s not a plant most gardeners will grow, knowing about species like this reminds us why protecting natural habitats is so important. These rare natives are living reminders of the incredible diversity that exists in our landscapes – if we’re careful to preserve it.
If you’re lucky enough to live in its native range and can find responsibly sourced plants, growing Bigelow’s thoroughwort could be a meaningful way to support conservation efforts. Just remember: when it comes to rare plants, responsibility comes first, gardening second.