North America Native Plant

Mearns’ Bird’s-foot Trefoil

Botanical name: Lotus mearnsii var. equisolensis

USDA symbol: LOMEE

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Mearns’ Bird’s-Foot Trefoil: A Rare Arizona Native Worth Protecting If you’re passionate about native plants and conservation gardening, you may have stumbled upon the intriguingly named Mearns’ bird’s-foot trefoil (Lotus mearnsii var. equisolensis). This little-known Arizona native is more than just a botanical curiosity—it’s a rare perennial forb that deserves ...

Rare plant alert!

Region: Conservation status by state

Status: S3T1: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Mearns’ Bird’s-Foot Trefoil: A Rare Arizona Native Worth Protecting

If you’re passionate about native plants and conservation gardening, you may have stumbled upon the intriguingly named Mearns’ bird’s-foot trefoil (Lotus mearnsii var. equisolensis). This little-known Arizona native is more than just a botanical curiosity—it’s a rare perennial forb that deserves our attention and protection.

What Makes This Plant Special?

Mearns’ bird’s-foot trefoil belongs to the legume family and shares the characteristic growth habit of a forb—meaning it’s a soft-stemmed, herbaceous plant without woody tissue above ground. As a perennial, it returns year after year, making it a potentially valuable addition to native plant gardens. However, there’s something crucial every gardener needs to know about this plant before considering it for their landscape.

A Plant Worth Protecting

Here’s where things get serious: Mearns’ bird’s-foot trefoil has a Global Conservation Status of S3T1, indicating it’s quite rare in the wild. This rarity status means that while we absolutely want to encourage its cultivation, it must be done responsibly. If you’re considering adding this plant to your garden, you should only source it from reputable native plant nurseries that can guarantee their stock comes from ethically collected seeds or propagated material—never from wild populations.

Where Does It Call Home?

This Arizona native has a very limited natural range, found only within the borders of the Grand Canyon State. Its restricted distribution is part of what makes it so special—and so vulnerable. Understanding its native habitat can help us provide better growing conditions in our gardens.

Should You Grow Mearns’ Bird’s-Foot Trefoil?

The answer is a cautious yes, but with important caveats:

  • Only if you can source it responsibly from reputable native plant suppliers
  • If you’re committed to supporting Arizona’s native plant diversity
  • If you’re interested in conservation gardening and preserving rare species
  • If you have growing conditions that can mimic its natural Arizona habitat

Growing Conditions and Care

While specific cultivation information for this rare variety is limited, we can make some educated assumptions based on its Arizona origins and forb growth habit:

  • Likely prefers well-draining soils typical of Arizona landscapes
  • Probably thrives in full sun to partial shade
  • As a desert native, it likely has low to moderate water needs once established
  • Being a legume, it may help improve soil nitrogen levels

The Bigger Picture

Growing rare native plants like Mearns’ bird’s-foot trefoil is about more than just having an unusual addition to your garden. It’s about participating in conservation efforts, supporting local ecosystems, and preserving genetic diversity for future generations. Every responsibly grown specimen in cultivation helps reduce pressure on wild populations and serves as a genetic backup.

What We Still Need to Learn

Honestly, there’s still much we don’t know about this rare plant’s specific growing requirements, wildlife benefits, and ecological relationships. This is precisely why responsible cultivation and study are so important. Home gardeners growing this species could contribute valuable observations about its growth habits, flowering times, and interactions with local wildlife.

The Bottom Line

Mearns’ bird’s-foot trefoil represents both an opportunity and a responsibility for native plant enthusiasts. If you can source it ethically and commit to growing it with care, you’ll be participating in an important conservation effort while adding a truly unique Arizona native to your landscape. Just remember—with rare plants comes great responsibility!

Mearns’ Bird’s-foot Trefoil

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Lotus L. - trefoil

Species

Lotus mearnsii (Britton) Greene - Mearns' bird's-foot trefoil

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA