North America Native Plant

Arrow Thelypody

Botanical name: Thelypodium sagittatum ovalifolium

USDA symbol: THSAO

Life cycle: biennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Thelypodium sagittatum (Nutt. ex Torr. & A. Gray) Endl. ex Walp. var. ovalifolium (Rydb.) S.L. Welsh & Reveal (THSAO2)  âš˜  Thelypodiopsis sagittata (Nutt. ex Torr. & A. Gray) O.E. Schulz var. ovalifolium (Rydb.) S.L. Welsh (THSAO3)   

Arrow Thelypody: A Rare Western Native Worth Knowing Meet the arrow thelypody (Thelypodium sagittatum ovalifolium), a fascinating native wildflower that’s definitely not your garden-variety plant! This member of the mustard family might not be on every gardener’s wish list, but it deserves a spot in the conversation about western native ...

Rare plant alert!

Region: Conservation status by state

Status: S4T2: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is 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) ⚘ 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 ⚘

Arrow Thelypody: A Rare Western Native Worth Knowing

Meet the arrow thelypody (Thelypodium sagittatum ovalifolium), a fascinating native wildflower that’s definitely not your garden-variety plant! This member of the mustard family might not be on every gardener’s wish list, but it deserves a spot in the conversation about western native plants and conservation gardening.

What Exactly Is Arrow Thelypody?

Arrow thelypody is a native forb—basically a non-woody flowering plant—that can live as either a biennial or perennial depending on conditions. Think of it as a wildflower that knows how to adapt! It belongs to the mustard family (Brassicaceae), which means it’s related to familiar plants like cabbage and radishes, though it looks quite different from its cultivated cousins.

You might also see this plant listed under its synonyms Thelypodium sagittatum var. ovalifolium or Thelypodiopsis sagittata var. ovalifolium in older botanical references—botanists love to shuffle names around!

Where Does It Call Home?

This native beauty has a pretty exclusive address list. Arrow thelypody naturally grows in just two states: Nevada and Utah. It’s truly a child of the Great Basin region, adapted to the unique conditions of this western landscape.

The Conservation Story

Here’s where things get serious for a moment. Arrow thelypody has a Global Conservation Status of S4T2, which indicates it has some level of conservation concern. This means it’s not exactly common in the wild, and we need to be thoughtful about how we interact with this species.

If you’re considering growing arrow thelypody, it’s crucial to source seeds or plants only from reputable native plant nurseries that propagate their stock rather than wild-collecting. Never collect seeds or plants from wild populations—let’s keep those populations healthy for future generations!

Garden Potential and Challenges

Let’s be honest: arrow thelypody isn’t going to win any easiest native plant to grow contests. As a specialized western native with limited distribution, it has specific needs that aren’t well-documented for home cultivation. This makes it more of a plant for serious native plant enthusiasts rather than beginning gardeners.

The lack of readily available growing information also means you’d be somewhat pioneering if you decide to try cultivating this species. While that can be exciting for experienced gardeners, it also means there’s no established roadmap for success.

Better Alternatives for Most Gardens

Unless you’re specifically working on habitat restoration in Nevada or Utah, or you’re a dedicated collector of rare natives, you might want to consider other mustard family natives that are better understood and more readily available. These could include:

  • Wild mustard species native to your specific region
  • Native wallflowers (Erysimum species)
  • Other regional Thelypodium species with better cultivation information

If You’re Determined to Try

Should you decide to work with arrow thelypody, remember that as a Great Basin native, it likely prefers:

  • Well-draining soils (probably alkaline, like much of its native range)
  • Full sun exposure
  • Minimal summer water once established
  • Cool, moist winters followed by warm, dry summers

As a forb, it won’t develop woody stems, and its perennating buds stay at or below ground level, helping it survive harsh winter conditions.

The Bottom Line

Arrow thelypody represents something special in the world of native plants—a reminder that not every species needs to be in cultivation to be valuable. Sometimes, the best way to appreciate a rare native is to support its wild populations and learn about similar, more available alternatives for our gardens.

If you’re gardening in Nevada or Utah and passionate about regional natives, arrow thelypody might be worth exploring with responsibly sourced material. For everyone else, it’s a plant to appreciate from afar while we focus on other native species that are better suited to cultivation and readily available without conservation concerns.

Arrow Thelypody

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Thelypodium Endl. - thelypody

Species

Thelypodium sagittatum (Nutt. ex Torr. & A. Gray) Endl. ex Walp. - arrow thelypody

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