North America Native Plant

Twocrested Milkvetch

Botanical name: Astragalus bicristatus

USDA symbol: ASBI

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Twocrested Milkvetch: A Rare California Native Worth Protecting Meet the twocrested milkvetch (Astragalus bicristatus), a little-known perennial legume that deserves a spot in every California native plant enthusiast’s heart. This unassuming wildflower might not make headlines, but it’s quietly playing an important role in California’s diverse ecosystem—and it could use ...

Rare plant alert!

Region: Conservation status by state

Status: S3: 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 ⚘

Twocrested Milkvetch: A Rare California Native Worth Protecting

Meet the twocrested milkvetch (Astragalus bicristatus), a little-known perennial legume that deserves a spot in every California native plant enthusiast’s heart. This unassuming wildflower might not make headlines, but it’s quietly playing an important role in California’s diverse ecosystem—and it could use our help.

What Makes Twocrested Milkvetch Special?

As a member of the pea family (Fabaceae), twocrested milkvetch shares the nitrogen-fixing superpowers that make legumes so valuable in natural ecosystems. This perennial native has adapted specifically to California’s unique climate and soil conditions, making it a true Golden State original.

The name twocrested refers to distinctive features on the plant’s seed pods, though you’ll need a keen eye to spot these botanical details. Like many of its Astragalus cousins, this species likely produces clusters of small, colorful flowers that add subtle beauty to the landscape.

Where Does It Call Home?

Twocrested milkvetch is endemic to California, meaning you won’t find it growing wild anywhere else on Earth. This exclusive California citizenship makes it extra special—and extra vulnerable.

A Plant That Needs Our Help

Here’s where things get serious: twocrested milkvetch has a Global Conservation Status of S3, which translates to Vulnerable. This means the species faces real challenges in the wild, with typically only 21 to 100 known populations and between 3,000 to 10,000 individual plants total. That might sound like a lot, but in botanical terms, it’s cause for concern.

This vulnerable status makes twocrested milkvetch an excellent choice for conservation-minded gardeners who want to make a real difference. By growing this species, you’re literally helping preserve California’s natural heritage.

Should You Plant Twocrested Milkvetch?

The short answer: Yes, but responsibly.

If you’re passionate about native plants and conservation, twocrested milkvetch could be a meaningful addition to your garden. However, given its rare status, it’s absolutely crucial that you source plants or seeds responsibly. Never collect from wild populations—this could harm already vulnerable communities.

Instead, look for:

  • Reputable native plant nurseries that propagate from ethically sourced material
  • Conservation organizations that may have cultivation programs
  • Native plant societies that might offer seeds from documented garden sources

Growing Twocrested Milkvetch

As with many California natives, twocrested milkvetch likely appreciates well-draining soil and minimal summer water once established. Based on its natural distribution, it should thrive in USDA hardiness zones 8-10, making it suitable for most of California’s gardening regions.

Here are some general guidelines for success:

  • Plant in fall or early spring
  • Choose a sunny to partially shaded location
  • Ensure excellent drainage—soggy soil is usually a death sentence for California natives
  • Water moderately during establishment, then reduce watering significantly
  • Avoid fertilizers, which can actually harm native plants adapted to nutrient-poor soils

Garden Design Ideas

Twocrested milkvetch works beautifully in:

  • Native plant gardens focused on California flora
  • Drought-tolerant landscapes
  • Pollinator gardens (legume flowers are excellent for native bees)
  • Conservation collections
  • Naturalized areas where you want to support local wildlife

Supporting Pollinators and Wildlife

Like other members of the pea family, twocrested milkvetch likely provides valuable nectar and pollen for native bees and other pollinators. The plant’s nitrogen-fixing abilities also improve soil health, benefiting neighboring plants and the broader ecosystem.

The Bottom Line

Twocrested milkvetch might not be the showiest plant in your garden, but it offers something even more valuable: the chance to participate in conservation while supporting California’s unique natural heritage. If you can source it responsibly and provide appropriate growing conditions, this rare native deserves consideration for your landscape.

Remember, every plant grown in cultivation is a small victory for conservation. By choosing natives like twocrested milkvetch, you’re creating habitat, supporting pollinators, and helping ensure that future generations will be able to enjoy California’s remarkable botanical diversity.

Just promise us you’ll be patient with this little legume—rare plants sometimes march to their own drumbeat, but that’s part of what makes them so worth growing.

Twocrested Milkvetch

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

Astragalus L. - milkvetch

Species

Astragalus bicristatus A. Gray - twocrested milkvetch

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