North America Native Plant

Harold’s Milkvetch

Botanical name: Astragalus robbinsii var. harringtonii

USDA symbol: ASROH

Life cycle: perennial

Habit: forb

Native status: Native to Alaska  

Synonyms: Astragalus harringtonii (Rydb.) Coville & Standl. ex Hultén (ASHA10)  âš˜  Astragalus robbinsii (Oakes) A. Gray ssp. harringtonii (Rydb.) Hultén (ASROH2)  âš˜  Atelophragma harringtonii Rydb. (ATHA2)   

Harold’s Milkvetch: A Rare Arctic Treasure for Specialized Gardens If you’re looking for something truly unique to add to your garden, Harold’s milkvetch (Astragalus robbinsii var. harringtonii) might just be the conversation starter you never knew you needed. This perennial plant is about as exclusive as it gets in the ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is 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. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Harold’s Milkvetch: A Rare Arctic Treasure for Specialized Gardens

If you’re looking for something truly unique to add to your garden, Harold’s milkvetch (Astragalus robbinsii var. harringtonii) might just be the conversation starter you never knew you needed. This perennial plant is about as exclusive as it gets in the gardening world – it’s found only in Alaska and belongs to a group of plants that most gardeners will never encounter in their local nursery.

What Makes Harold’s Milkvetch Special?

Harold’s milkvetch is a perennial member of the legume family, native exclusively to Alaska. This plant represents a fascinating example of Arctic adaptation, having evolved to thrive in some of North America’s most challenging growing conditions. Like other milkvetches, it’s part of the Astragalus genus, which includes hundreds of species known for their ability to fix nitrogen in the soil.

Where Does It Grow?

This remarkable plant calls Alaska home and only Alaska. Its extremely limited geographic distribution makes it a true regional specialty that has adapted to the unique conditions of the far north.

Should You Grow Harold’s Milkvetch?

Here’s where things get interesting – and a bit complicated. Harold’s milkvetch has a conservation status that suggests it may be uncommon or specialized in its habitat requirements. This means a few important things for potential growers:

  • It’s likely adapted to very specific Arctic or subarctic conditions
  • Seeds or plants should only be obtained from responsible, ethical sources
  • It may require specialized growing conditions that are difficult to replicate outside its native range
  • Consider it more of a conservation project than a typical garden addition

Growing Conditions and Care

While specific cultivation information for this variety is limited, we can make some educated guesses based on its Alaskan heritage and membership in the Astragalus family:

  • Likely requires excellent drainage (most Arctic plants do)
  • Probably needs a significant cold period (winter chill hours)
  • May prefer lean, rocky, or sandy soils rather than rich garden soil
  • Likely adapted to long summer days and short growing seasons
  • May be extremely difficult to grow in warmer climates

The Bottom Line

Harold’s milkvetch is more of a botanical curiosity than a practical garden choice for most people. Unless you’re in Alaska, have experience with alpine or Arctic plants, and are committed to conservation-minded gardening, this probably isn’t the plant for you.

If you’re drawn to the idea of growing native milkvetches, consider looking for Astragalus species that are native to your own region instead. Many areas have their own fascinating milkvetch species that are better adapted to local conditions and more readily available through responsible sources.

For those truly dedicated to growing this rare variety, work only with specialized native plant societies, botanical gardens, or research institutions that can provide ethically sourced material and proper growing guidance. Remember, with rare plants like this one, conservation always comes first.

Harold’s 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 robbinsii (Oakes) A. Gray - Robbins' milkvetch

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