Chase’s Threeawn: A Critically Endangered Puerto Rican Native Worth Protecting
Meet Chase’s threeawn (Aristida chaseae), a remarkable little grass that’s fighting for survival in its native Puerto Rico. This perennial graminoid might not be the showiest plant in the botanical world, but its story is one that every conservation-minded gardener should know.
What Makes Chase’s Threeawn Special
Chase’s threeawn is a delicate, fine-textured native grass that belongs to the diverse Aristida genus. Like its relatives, this species produces the characteristic three-awned seeds that give threeawn grasses their common name. The plant forms clumps of narrow, thread-like leaves topped with airy seed heads that dance gracefully in coastal breezes.
A Grass in Crisis
Here’s the critical part every gardener needs to know: Chase’s threeawn is critically endangered with a Global Conservation Status of S1?, meaning it’s extremely rare with typically five or fewer known occurrences. In the United States (which includes Puerto Rico), it’s officially listed as Endangered.
This isn’t just another rare plant—it’s a species teetering on the edge of extinction, making every individual plant incredibly precious for biodiversity conservation.
Where Chase’s Threeawn Calls Home
This endemic species is found exclusively in Puerto Rico, where it grows in dry coastal areas and limestone hills. Its entire world range is limited to this single Caribbean island, making it one of nature’s true specialists.
Growing Conditions and Habitat Needs
In its natural habitat, Chase’s threeawn thrives in:
- Well-draining, often rocky or sandy soils
- Full sun exposure
- Dry conditions with minimal water requirements
- USDA hardiness zones 10-11 (tropical and subtropical climates)
The plant has adapted to Puerto Rico’s challenging coastal and limestone hill environments, developing excellent drought tolerance once established.
Should You Plant Chase’s Threeawn?
Given its critically endangered status, we strongly recommend extreme caution. If you’re passionate about growing this species:
- Only obtain plants from verified, responsible sources that can guarantee the material wasn’t collected from wild populations
- Consider supporting conservation organizations working to protect this species instead
- If you do grow it, participate in seed collection and sharing programs to help build genetic diversity in cultivation
- Never collect plants or seeds from the wild
Landscape Role and Design Considerations
For those in appropriate climates with responsibly sourced plants, Chase’s threeawn can serve as:
- An accent grass in xerophytic (drought-adapted) garden designs
- Part of native Puerto Rican landscape restorations
- A conservation planting in botanical gardens or educational settings
- Groundcover for challenging, dry sites
Wildlife and Ecological Benefits
As a native grass, Chase’s threeawn likely provides habitat and food sources for native insects and small wildlife, though specific relationships aren’t well-documented due to the species’ rarity. Grasses in general offer nesting materials and seeds for various bird species.
Care and Maintenance
If you’re growing Chase’s threeawn with proper authorization and sourcing:
- Provide excellent drainage—this is non-negotiable
- Water sparingly once established
- Give it full sun exposure
- Avoid fertilizers, which can harm native grasses adapted to nutrient-poor soils
- Allow the plant to go through natural seasonal cycles
The Bigger Picture
Chase’s threeawn represents the fragility of island ecosystems and the importance of plant conservation. While most gardeners won’t have the opportunity to grow this rare species, learning about plants like Chase’s threeawn reminds us why choosing native plants for our own regions matters so much.
Instead of seeking out this endangered species, consider researching and planting native grasses in your own area. Every garden filled with appropriate native plants is a small victory for biodiversity and a step toward preventing other species from reaching the critical state that Chase’s threeawn faces today.
