North America Native Plant

Tall Milkvetch

Botanical name: Astragalus altus

USDA symbol: ASAL8

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Tall Milkvetch: A Rare Desert Gem Worth Protecting Meet tall milkvetch (Astragalus altus), one of New Mexico’s most precious botanical treasures. This perennial wildflower might not be the showiest plant in the garden, but what it lacks in flashiness, it makes up for in ecological importance and rarity that makes ...

Rare plant alert!

Region: Conservation status by state

Status: S2: Status is uncertain but is somewhere between the following rankings: Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘

Tall Milkvetch: A Rare Desert Gem Worth Protecting

Meet tall milkvetch (Astragalus altus), one of New Mexico’s most precious botanical treasures. This perennial wildflower might not be the showiest plant in the garden, but what it lacks in flashiness, it makes up for in ecological importance and rarity that makes it truly special.

What Makes Tall Milkvetch Special?

Tall milkvetch is a native perennial that belongs to the pea family, sporting the characteristic compound leaves and small, pea-like flowers that range from purple to pink. Like other members of the Astragalus genus, this plant has adapted beautifully to harsh desert conditions, making it a fascinating study in plant resilience.

But here’s the catch – and it’s a big one – tall milkvetch has a Global Conservation Status of S2, meaning it’s imperiled. With typically only 6 to 20 occurrences and fewer than 3,000 individuals remaining in the wild, this plant is extremely rare and vulnerable to extinction.

Where Does Tall Milkvetch Call Home?

This desert dweller is endemic to New Mexico, where it has carved out its niche in the state’s unique high desert ecosystems. Its limited range makes it all the more precious to those lucky enough to encounter it in the wild.

Should You Grow Tall Milkvetch?

Here’s where things get serious, fellow gardeners. While tall milkvetch would make a wonderful addition to native plant collections and xerophytic gardens, its rarity status means we need to approach cultivation very carefully.

If you’re considering growing tall milkvetch, please only do so with responsibly sourced material. Never collect from wild populations – these plants are too rare and precious to risk. Instead, work with reputable native plant nurseries or conservation organizations that may have ethically propagated specimens.

Perfect Growing Conditions

If you can source tall milkvetch responsibly, here’s what this desert native needs to thrive:

  • Sunlight: Full sun exposure
  • Soil: Well-draining soils are absolutely essential
  • Water: Minimal watering once established – this plant is built for drought
  • Climate: Hardy in USDA zones 5-8
  • Garden style: Perfect for rock gardens, xerophytic landscapes, or specialized native plant collections

Garden Role and Design Ideas

In the right garden setting, tall milkvetch serves as both a conversation starter and a conservation statement. It works beautifully in:

  • Rock gardens where its drought tolerance shines
  • Native plant collections focused on regional species
  • Educational gardens that highlight plant conservation
  • Xerophytic landscapes that celebrate desert adaptations

Pollinator and Wildlife Benefits

Like other legumes, tall milkvetch attracts native bees and other pollinators with its protein-rich flowers. The plant also fixes nitrogen in the soil, making it a valuable ecosystem player that benefits neighboring plants.

Care Tips for Success

The secret to growing tall milkvetch successfully lies in mimicking its natural desert habitat:

  • Ensure excellent drainage – soggy soils are this plant’s worst enemy
  • Water sparingly, especially once established
  • Avoid rich, fertile soils that might encourage weak, leggy growth
  • Plant in full sun locations
  • Be patient – desert plants often grow slowly but reward persistence

A Plant Worth Protecting

While tall milkvetch might not be the easiest plant to find or grow, it represents something incredibly important in our native plant world – a species that needs our protection and careful stewardship. If you’re lucky enough to grow this rare beauty, you’re not just adding a unique plant to your garden; you’re participating in conservation efforts that could help ensure this species survives for future generations.

For most gardeners, the best way to appreciate tall milkvetch might be supporting conservation efforts and choosing other native New Mexico plants that are more readily available and less vulnerable. Every native plant we grow helps support local ecosystems, and sometimes the most caring choice is to admire rare species from afar while we nurture their more common cousins.

Tall 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 altus Wooton & Standl. - tall milkvetch

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