North America Native Plant

Long Valley Tumblemustard

Botanical name: Thelypodiopsis ambigua

USDA symbol: THAM3

Life cycle: biennial

Habit: forb

Native status: Native to the lower 48 states  

Long Valley Tumblemustard: A Rare Native Gem for Southwestern Gardens If you’re passionate about growing truly native plants and supporting local ecosystems, you might want to learn about Long Valley tumblemustard (Thelypodiopsis ambigua). This little-known biennial belongs to the mustard family and represents one of those special native species that ...

Rare plant alert!

Region: Conservation status by state

Status: S2S3: 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) ⚘ 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 ⚘

Long Valley Tumblemustard: A Rare Native Gem for Southwestern Gardens

If you’re passionate about growing truly native plants and supporting local ecosystems, you might want to learn about Long Valley tumblemustard (Thelypodiopsis ambigua). This little-known biennial belongs to the mustard family and represents one of those special native species that deserves more attention from dedicated native plant gardeners.

Where Does Long Valley Tumblemustard Call Home?

Long Valley tumblemustard is native to the southwestern United States, specifically found in Arizona and Utah. This regional native has adapted to the unique conditions of the American Southwest, making it a true local treasure for gardeners in these areas.

What Makes This Plant Special?

As a biennial forb, Long Valley tumblemustard follows a two-year life cycle. In its first year, it focuses on establishing roots and foliage, then flowers and sets seed in its second year before completing its life cycle. Like other members of the mustard family, it’s an herbaceous plant without woody stems, keeping all its growth at or near ground level.

Important Conservation Considerations

Here’s something every responsible gardener should know: Long Valley tumblemustard has a Global Conservation Status of S2S3, which indicates this species may face some conservation challenges. This rarity status means that if you’re interested in growing this plant, it’s crucial to source it responsibly.

What this means for you:

  • Only obtain plants or seeds from reputable native plant nurseries
  • Never collect from wild populations
  • Consider this plant as part of conservation gardening efforts
  • Contact local native plant societies for guidance on responsible sourcing

Growing Long Valley Tumblemustard

Unfortunately, detailed growing information for this species is quite limited, which isn’t uncommon for rare native plants. Based on its natural habitat in Arizona and Utah, we can make some educated assumptions about its preferences:

  • Likely thrives in well-draining soils typical of southwestern regions
  • Probably adapted to lower water conditions once established
  • May prefer full sun to partial shade
  • Being a biennial, expect a two-year growing cycle

Should You Grow Long Valley Tumblemustard?

This plant might be perfect for you if:

  • You’re located in Arizona or Utah
  • You’re passionate about growing rare native species
  • You want to support local biodiversity
  • You’re working on a conservation-focused garden project

However, you might want to consider alternatives if:

  • You’re looking for a well-documented, easy-to-grow plant
  • You want immediate garden impact (remember, it’s a biennial)
  • You can’t find responsibly sourced material

The Bottom Line

Long Valley tumblemustard represents the kind of plant that makes native gardening both challenging and rewarding. While information about this species is limited, its rarity and native status make it a worthy consideration for dedicated native plant enthusiasts in the Southwest. If you can source it responsibly and you’re prepared for the patience that biennial plants require, you’ll be growing a true piece of your local natural heritage.

Before planting, we recommend connecting with local native plant societies, botanical gardens, or extension offices in Arizona and Utah for the most current information about availability and growing tips specific to your area.

Long Valley Tumblemustard

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

Thelypodiopsis Rydb. - tumblemustard

Species

Thelypodiopsis ambigua (S. Watson) Al-Shehbaz - Long Valley tumblemustard

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