North America Native Plant

Santa Cruz Island Ticktrefoil

Botanical name: Desmodium psilocarpum

USDA symbol: DEPS

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Santa Cruz Island Ticktrefoil: A Hidden Gem for Southwestern Native Gardens If you’re looking to add authentic southwestern charm to your native garden, Santa Cruz Island ticktrefoil (Desmodium psilocarpum) might just be the unsung hero you’ve been searching for. This delightful little forb brings both beauty and ecological value to ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: Status is uncertain but is somewhere between the following rankings: 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 ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Santa Cruz Island Ticktrefoil: A Hidden Gem for Southwestern Native Gardens

If you’re looking to add authentic southwestern charm to your native garden, Santa Cruz Island ticktrefoil (Desmodium psilocarpum) might just be the unsung hero you’ve been searching for. This delightful little forb brings both beauty and ecological value to gardens across the American Southwest, though you might need to do a bit of detective work to find it!

What Makes This Plant Special?

Santa Cruz Island ticktrefoil is a true native of the southwestern United States, calling Arizona and New Mexico home. As a member of the pea family, this herbaceous plant showcases the classic three-leaflet compound leaves that give it part of its trefoil name. But don’t let its humble appearance fool you – this little powerhouse packs plenty of garden appeal.

The plant produces charming clusters of small, pea-like flowers that range from pink to purple, creating delicate splashes of color in the landscape. These blooms eventually give way to interesting seed pods covered in tiny hooked hairs – nature’s clever way of ensuring the seeds hitch rides to new locations.

Where You’ll Find It Growing Wild

This ticktrefoil has carved out its niche in the desert Southwest, thriving in Arizona and New Mexico’s unique climate conditions. It’s perfectly adapted to the challenging conditions of this region, making it an excellent choice for gardeners working with similar environmental constraints.

A Word About Rarity

Here’s something important to know: Santa Cruz Island ticktrefoil carries a conservation status of S3S4, which suggests it’s not as common as some other native plants. This doesn’t mean you shouldn’t grow it – quite the opposite! By including it in your garden, you’re helping preserve this lovely species. Just make sure you source your plants or seeds from reputable native plant nurseries that collect responsibly.

Garden Appeal and Design Uses

This versatile forb works beautifully in several garden settings:

  • Native plant gardens where authenticity matters
  • Xeriscape designs focused on water conservation
  • Naturalistic landscapes that mimic wild southwestern habitats
  • Pollinator gardens supporting local wildlife

Its relatively low, spreading growth habit makes it perfect for filling in gaps between larger shrubs or creating natural-looking ground cover areas. The plant can function as either an annual or perennial depending on growing conditions, giving you flexibility in your garden planning.

Wildlife and Pollinator Benefits

Like many members of the pea family, Santa Cruz Island ticktrefoil is a magnet for pollinators. Bees absolutely love the protein-rich pollen and nectar from those small but abundant flowers. Butterflies and other beneficial insects also make regular visits, turning your garden into a bustling hub of activity.

The seeds, despite their hitchhiking tendencies, also provide food for various seed-eating birds and small wildlife, extending the plant’s ecological value well beyond its blooming period.

Growing Conditions and Care

One of the best things about this native is how well it’s adapted to southwestern growing conditions. Here’s what it prefers:

  • Sunlight: Full sun to partial shade
  • Soil: Well-draining soils (clay, sandy, or rocky)
  • Water: Drought tolerant once established
  • Climate: USDA zones 7-10

This is definitely a set it and forget it kind of plant once it’s established in your garden. It’s naturally adapted to the feast-or-famine water patterns of the Southwest, so it won’t demand constant irrigation like many non-native alternatives.

Planting and Care Tips

Getting started with Santa Cruz Island ticktrefoil is refreshingly straightforward:

  • Plant in spring after the last frost date
  • Provide regular water during the first growing season to help establishment
  • Once established, water only during extended dry periods
  • Avoid over-fertilizing – this plant thrives in lean soils
  • Allow some seed pods to mature if you want natural reseeding

The plant’s ability to function as either an annual or perennial means you might see different behaviors depending on your specific microclimate and care routine. Don’t be surprised if it acts more like an annual in harsher conditions or more like a perennial with a bit of extra care.

Is This Plant Right for Your Garden?

Santa Cruz Island ticktrefoil is an excellent choice if you’re gardening in the Southwest and want to create authentic native plant communities. It’s particularly valuable for gardeners interested in supporting local ecosystems while working with plants that can handle challenging growing conditions.

However, since this species has some rarity concerns, make sure you’re sourcing it responsibly. Look for nurseries that specialize in native plants and can verify their collection practices. By choosing this plant, you’re not just adding beauty to your garden – you’re participating in conservation efforts for southwestern flora.

For gardeners outside its native range, consider exploring similar native Desmodium species that might be more appropriate for your local ecosystem. Every region has its own wonderful ticktrefoils waiting to be discovered!

Santa Cruz Island Ticktrefoil

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

Desmodium Desv. - ticktrefoil

Species

Desmodium psilocarpum A. Gray - Santa Cruz Island ticktrefoil

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