North America Native Plant

Groundplum Milkvetch

Botanical name: Astragalus crassicarpus var. crassicarpus

USDA symbol: ASCRC3

Life cycle: perennial

Habit: forb

Native status: Native to Canada âš˜ Native to the lower 48 states  

Synonyms: Astragalus caryocarpus Ker Gawl. (ASCA28)  âš˜  Astragalus succulentus Richardson (ASSU12)  âš˜  Geoprumnon crassicarpum (Nutt.) Rydb. ex Small (GECR5)  âš˜  Geoprumnon succulentum (Richardson) Rydb. (GESU)   

Groundplum Milkvetch: A Prairie Gem for Your Native Garden If you’re looking to add a touch of prairie magic to your landscape, groundplum milkvetch (Astragalus crassicarpus var. crassicarpus) might just be the quirky native plant you’ve been searching for. This delightful perennial doesn’t just bring beautiful purple blooms to your ...

Rare plant alert!

Region: Arkansas

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) ⚘

Groundplum Milkvetch: A Prairie Gem for Your Native Garden

If you’re looking to add a touch of prairie magic to your landscape, groundplum milkvetch (Astragalus crassicarpus var. crassicarpus) might just be the quirky native plant you’ve been searching for. This delightful perennial doesn’t just bring beautiful purple blooms to your garden – it also produces some of the most interesting seed pods you’ll ever see, earning it the charming groundplum nickname.

What Makes Groundplum Milkvetch Special?

Groundplum milkvetch is a true North American native, naturally occurring across the Great Plains and prairie regions from Canada down through the central United States. You’ll find this hardy perennial thriving in states like Kansas, Nebraska, Colorado, Wyoming, and many others, as well as in Canadian provinces including Alberta, Saskatchewan, and Manitoba.

The plant gets its common name from its distinctive inflated seed pods that look remarkably like small, plump fruits. These fascinating pods follow clusters of purple, pea-like flowers that bloom in late spring, creating a delightful two-season display that’s sure to spark conversations with garden visitors.

Why Grow Groundplum Milkvetch?

There are plenty of reasons to consider adding this prairie native to your landscape:

  • Drought tolerance: Once established, this plant thrives with minimal water, making it perfect for xeriscaping and water-wise gardens
  • Pollinator magnet: The purple flowers attract bees, butterflies, and other beneficial insects to your garden
  • Low maintenance: As a hardy perennial, it comes back year after year with little fuss
  • Unique appearance: Those inflated seed pods are real showstoppers and add textural interest
  • Native plant benefits: Supports local ecosystems and wildlife

Perfect Garden Settings

Groundplum milkvetch shines in several garden styles:

  • Prairie and meadow gardens
  • Rock gardens and xeriscapes
  • Native plant landscapes
  • Naturalized areas
  • Wildlife-friendly gardens

Growing Conditions and Care

This adaptable native is surprisingly easy to grow when you give it what it wants. Groundplum milkvetch thrives in USDA hardiness zones 3-8, making it suitable for a wide range of climates.

Soil requirements: Well-draining soil is essential – this plant absolutely hates wet feet. It adapts to various soil types but prefers sandy or gravelly conditions that mimic its natural prairie habitat.

Sun exposure: Full sun is best for optimal flowering and pod development. While it can tolerate some light shade, you’ll get the best performance in bright, sunny locations.

Watering: Once established, groundplum milkvetch is remarkably drought-tolerant. Water regularly during the first growing season to help establish roots, then step back and let nature take over.

Planting and Propagation Tips

Growing groundplum milkvetch from seed can be a bit tricky since the seeds have hard coats that benefit from scarification (lightly scratching or nicking the seed coat) before planting. You can also try cold stratification by storing seeds in the refrigerator for several weeks before sowing.

Plant seeds in fall for natural winter stratification, or start them indoors in late winter. Space plants about 12-18 inches apart to allow for their spreading growth habit.

Important Conservation Note

While groundplum milkvetch isn’t considered invasive or noxious, it does have a rarity status of S2 in Arkansas, meaning it’s considered rare in that state. If you’re gardening in Arkansas or other areas where the plant might be uncommon, please source your plants or seeds responsibly from reputable native plant nurseries rather than collecting from wild populations.

The Bottom Line

Groundplum milkvetch offers the perfect combination of beauty, functionality, and low maintenance that every native plant enthusiast dreams of. Its purple spring flowers and fascinating inflated pods make it a conversation starter, while its drought tolerance and pollinator appeal make it a practical choice for sustainable gardening. Whether you’re creating a prairie restoration project or simply want to add some native character to your landscape, this charming milkvetch deserves a spot in your garden plans.

Groundplum 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 crassicarpus Nutt. - groundplum milkvetch

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