North America Native Plant

Howell’s Thelypody

Botanical name: Thelypodium howellii spectabilis

USDA symbol: THHOS2

Life cycle: biennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Thelypodium howellii S. Watson var. spectabilis M. Peck (THHOS)   

Howell’s Thelypody: A Rare Oregon Native Worth Protecting Meet Howell’s thelypody (Thelypodium howellii spectabilis), a plant that’s both a hidden gem and a conservation concern rolled into one unassuming package. This native Oregon forb might not win any flashy flower contests, but it holds a special place in the hearts ...

Rare plant alert!

Region: United States

Status: S2T1: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ 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) ⚘ Threatened: Experiencing significant population decline or habitat loss that could lead to its endangerment if not addressed. ⚘

Region: United States

Howell’s Thelypody: A Rare Oregon Native Worth Protecting

Meet Howell’s thelypody (Thelypodium howellii spectabilis), a plant that’s both a hidden gem and a conservation concern rolled into one unassuming package. This native Oregon forb might not win any flashy flower contests, but it holds a special place in the hearts of native plant enthusiasts and conservationists across the Pacific Northwest.

What Makes This Plant Special

Howell’s thelypody belongs to the mustard family and produces clusters of small, delicate flowers that range from white to pale yellow. As a biennial or short-lived perennial forb, it lacks woody stems and instead sends up herbaceous growth from ground level each growing season. Don’t expect towering heights – this is a modest plant that lets its rarity, rather than its stature, do the talking.

A True Oregon Original

This plant is as Oregon as it gets, with its entire natural range confined to the state’s borders. While many native plants have expansive ranges spanning multiple states or even countries, Howell’s thelypody has chosen to make Oregon its one and only home. This limited distribution makes every single plant incredibly valuable from a conservation perspective.

The Rarity Factor: Why You Should Care

Important Conservation Alert: Howell’s thelypody carries a Threatened status and has a Global Conservation Status of S2T1. This means we’re dealing with a plant that’s genuinely at risk of disappearing from our landscapes forever. If you’re considering adding this species to your garden, please ensure you’re obtaining seeds or plants only from reputable sources that practice responsible collection methods.

Garden Role and Landscape Use

Let’s be honest – you’re probably not choosing Howell’s thelypody for its knockout blooms or impressive size. Instead, this plant serves a much more important purpose:

  • Conservation gardens focused on preserving Oregon’s native flora
  • Educational landscapes that showcase rare and threatened species
  • Native plant collections maintained by serious enthusiasts
  • Restoration projects in appropriate habitat areas

Supporting Local Pollinators

Despite its modest appearance, Howell’s thelypody pulls its weight when it comes to supporting local wildlife. Like other members of the mustard family, it produces flowers that attract small native bees and other pollinators. Every flower cluster becomes a tiny refueling station for Oregon’s native insects.

Growing Howell’s Thelypody Responsibly

Given this plant’s threatened status, growing it successfully requires extra consideration and care. Based on its Oregon origins, it likely thrives in USDA hardiness zones 7-9, though specific cultivation information remains limited due to its rarity.

Essential Growing Tips

  • Source responsibly: Only obtain seeds or plants from reputable native plant nurseries or conservation organizations
  • Soil preferences: Provide well-draining soil conditions typical of its native Oregon habitat
  • Moisture needs: Moderate watering, avoiding both drought stress and waterlogged conditions
  • Garden placement: Choose a spot where you can monitor and protect this valuable plant

The Bottom Line

Howell’s thelypody isn’t for every gardener or every garden situation. It’s a plant that asks for commitment, responsibility, and genuine care for conservation. If you’re drawn to rare native plants and want to contribute to preserving Oregon’s unique botanical heritage, this species could be a meaningful addition to your garden.

However, remember that with great rarity comes great responsibility. By choosing to grow Howell’s thelypody, you’re becoming a steward of a threatened species. Make sure you’re ready for that role before adding this special Oregon native to your landscape.

Consider this plant if you’re passionate about native plant conservation, have experience with challenging species, and can commit to sourcing and growing it ethically. Your garden could become a small but important refuge for one of Oregon’s most precious botanical treasures.

Howell’s 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 howellii S. Watson - Howell's thelypody

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