Mearns’ Bird’s-Foot Trefoil: A Rare Arizona Native Worth Protecting
Meet Mearns’ bird’s-foot trefoil (Lotus mearnsii), one of Arizona’s lesser-known botanical treasures. This perennial wildflower might not be on every gardener’s wish list, but it deserves our attention—and our protection.
A Rare Desert Gem
Mearns’ bird’s-foot trefoil is what botanists call a forb—essentially a non-woody flowering plant that dies back to the ground each winter and returns the following spring. But don’t let its humble classification fool you. This little plant carries big conservation significance.
With a Global Conservation Status of S3, this species is considered vulnerable. That means it’s either very rare throughout its range or faces other factors that could lead to its disappearance. Current estimates suggest there are only 21 to 100 known populations, with somewhere between 3,000 and 10,000 individual plants in existence.
Where to Find It (Or Not Find It)
Lotus mearnsii calls Arizona home and only Arizona. This makes it what we call an endemic species—a plant that exists nowhere else on Earth naturally. Talk about putting all your eggs in one basket!
Should You Grow Mearns’ Bird’s-Foot Trefoil?
Here’s where things get a bit complicated. While we’d love to encourage everyone to grow native plants, Mearns’ bird’s-foot trefoil presents a special case. Its rarity means that any seeds or plants you might encounter should be obtained only through responsible, ethical sources—never collected from wild populations.
If you’re lucky enough to find responsibly sourced material, growing this plant in your Arizona garden could contribute to its conservation. However, given the limited information available about its specific growing requirements, it might be challenging for the average home gardener.
What We Know About Growing Conditions
Unfortunately, detailed cultivation information for Lotus mearnsii is scarce. As a member of the legume family and a native Arizona perennial forb, we can make some educated guesses about its preferences:
- Likely adapted to Arizona’s arid climate
- Probably drought-tolerant once established
- May prefer well-draining soils typical of desert regions
- As a legume, it might fix nitrogen in the soil
The Conservation Angle
Sometimes the best way to help a rare plant isn’t to grow it in your garden, but to support its conservation in the wild. Consider:
- Supporting organizations that work to protect Arizona’s native flora
- Participating in citizen science projects that monitor rare plants
- Choosing other native Arizona plants that provide similar ecological benefits but aren’t at risk
Alternative Native Choices
While you’re waiting for more information about Lotus mearnsii cultivation, consider other Arizona native legumes that can provide similar benefits to your garden and local ecosystems. Desert lupines, fairy dusters, and other members of the pea family offer beautiful flowers and nitrogen-fixing abilities without the conservation concerns.
The Bottom Line
Mearns’ bird’s-foot trefoil represents both the beauty and fragility of Arizona’s unique flora. While it might not be the easiest plant to add to your garden right now, being aware of its existence and conservation needs makes you a more informed native plant gardener. Sometimes the plants we can’t grow teach us just as much as the ones we can.
If you do encounter opportunities to grow this rare beauty, proceed thoughtfully and always ensure your sources are ethical and conservation-minded. After all, the goal isn’t just a beautiful garden—it’s preserving Arizona’s irreplaceable natural heritage for future generations.
