North America Native Plant

Blunt Tansymustard

Botanical name: Descurainia obtusa obtusa

USDA symbol: DEOBO

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Descurainia obtusa (Greene) O.E. Schulz ssp. brevisiliqua Detling (DEOBB)  âš˜  Descurainia obtusa (Greene) O.E. Schulz ssp. typica Detling (DEOBT)   

Blunt Tansymustard: A Delicate Desert Native Worth Getting to Know If you’re looking to add some understated charm to your southwestern garden, meet blunt tansymustard (Descurainia obtusa obtusa). This petite annual might not win any flashy flower contests, but it brings a quiet elegance and ecological value that makes it ...

Rare plant alert!

Region: Conservation status by state

Status: S4S5T2T4: 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 ⚘ Subspecies or varieties is apparently secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the region or more than 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. ⚘

Blunt Tansymustard: A Delicate Desert Native Worth Getting to Know

If you’re looking to add some understated charm to your southwestern garden, meet blunt tansymustard (Descurainia obtusa obtusa). This petite annual might not win any flashy flower contests, but it brings a quiet elegance and ecological value that makes it a worthy addition to the right garden setting.

What Exactly is Blunt Tansymustard?

Blunt tansymustard is a native annual forb that belongs to the mustard family. As a forb, it’s essentially a non-woody flowering plant that completes its life cycle in one year (though it can occasionally behave as a biennial). Don’t let the mustard in its name fool you into thinking it’s related to your sandwich condiment – this is a wild relative that’s perfectly at home in the American Southwest.

You might also encounter this plant listed under its synonyms Descurainia obtusa ssp. brevisiliqua or Descurainia obtusa ssp. typica in older botanical references, but they’re all referring to the same charming little plant.

Where Does It Call Home?

This desert dweller is native to three southwestern states: Arizona, Nevada, and New Mexico. It’s perfectly adapted to the challenging conditions of the American Southwest, where it has evolved to thrive in environments that would leave many other plants gasping for water.

Why You Might Want to Grow Blunt Tansymustard

While blunt tansymustard won’t provide the jaw-dropping drama of a desert marigold or the architectural presence of an agave, it offers several compelling reasons to include it in your garden:

  • True native credentials: It’s genuinely native to the southwestern United States, making it an authentic choice for regional gardens
  • Low maintenance: Once established, it requires minimal care and water
  • Pollinator friendly: Its small yellow flowers attract beneficial insects and native pollinators
  • Natural reseeding: As an annual, it often self-seeds, creating natural drifts over time
  • Delicate beauty: Its fernlike foliage and clusters of tiny flowers add texture and subtle interest

Perfect Garden Settings

Blunt tansymustard shines in specific garden contexts:

  • Desert and xeriscape gardens: Its drought tolerance makes it perfect for water-wise landscapes
  • Native plant gardens: An authentic choice for southwestern native plant collections
  • Naturalized areas: Ideal for creating casual, meadow-like spaces
  • Wildlife gardens: Supports native pollinators and beneficial insects

Growing Conditions and Care

The good news is that blunt tansymustard is refreshingly undemanding. Here’s what it needs to thrive:

  • Sunlight: Full sun is best, though it can tolerate some light shade
  • Soil: Well-draining soil is essential – it won’t tolerate waterlogged conditions
  • Water: Drought tolerant once established, requiring minimal supplemental irrigation
  • USDA Zones: Hardy in zones 4-9, making it suitable for a wide range of climates

Planting and Care Tips

Growing blunt tansymustard successfully is surprisingly straightforward:

  • Timing: Direct seed in fall for spring germination, mimicking natural patterns
  • Seeding: Scatter seeds on prepared soil surface and lightly rake in
  • Watering: Provide occasional water during establishment, then reduce significantly
  • Maintenance: Minimal care needed – this plant prefers benign neglect
  • Self-seeding: Allow some plants to go to seed for natural population renewal

A Few Considerations

While blunt tansymustard is a lovely addition to appropriate gardens, keep these points in mind:

  • It’s best suited to its native southwestern range – gardeners in other regions might find better success with local natives
  • Its modest appearance means it’s not ideal if you’re looking for bold, showy displays
  • As an annual, you’ll need to allow for reseeding or replant each year

The Bottom Line

Blunt tansymustard is one of those quiet garden gems that rewards close observation rather than demanding attention from across the yard. If you’re gardening in the Southwest and want to support local ecosystems while adding delicate texture to your landscape, this native annual deserves consideration. It’s particularly valuable in naturalized settings where its self-seeding habit can create beautiful, ever-changing displays year after year.

For gardeners outside its native range, consider seeking out similar native mustard family plants that are indigenous to your area – every region has its own special natives waiting to be discovered and appreciated.

Blunt Tansymustard

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

Descurainia Webb & Bethel. - tansymustard

Species

Descurainia obtusa (Greene) O.E. Schulz - blunt tansymustard

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