North America Native Plant

Cusick’s Fumewort

Botanical name: Corydalis caseana cusickii

USDA symbol: COCAC

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Corydalis caseana A. Gray var. cusickii (S. Watson) C.L. Hitchc. (COCAC2)  âš˜  Corydalis cusickii S. Watson (COCU3)   

Cusick’s Fumewort: A Rare Pacific Northwest Native Worth Knowing Meet Cusick’s fumewort (Corydalis caseana cusickii), a charming native wildflower that might just be the hidden gem your Pacific Northwest garden has been waiting for. This delicate perennial forb brings a touch of wilderness elegance to landscapes, though you’ll need to ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ 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. ⚘

Cusick’s Fumewort: A Rare Pacific Northwest Native Worth Knowing

Meet Cusick’s fumewort (Corydalis caseana cusickii), a charming native wildflower that might just be the hidden gem your Pacific Northwest garden has been waiting for. This delicate perennial forb brings a touch of wilderness elegance to landscapes, though you’ll need to do a bit of detective work to find it!

What Makes Cusick’s Fumewort Special

Cusick’s fumewort belongs to the fascinating world of native forbs – those herbaceous plants that lack woody stems but pack plenty of character. As a perennial, this plant returns year after year, gradually establishing itself as a reliable garden resident. You might also encounter this beauty under its scientific synonyms: Corydalis caseana var. cusickii or simply Corydalis cusickii.

Where Does It Call Home?

This native treasure has made its home in the rugged landscapes of Idaho and Oregon, where it has adapted to local growing conditions over thousands of years. As a true native to the lower 48 states, Cusick’s fumewort represents the authentic flora of the Pacific Northwest region.

A Word of Caution: Rarity Matters

Here’s where things get interesting – and important. Cusick’s fumewort carries a Global Conservation Status of S5T3?, which signals some uncertainty about its population status. While we don’t have definitive invasive or noxious classifications for this plant, its rarity status means we need to be thoughtful gardeners.

If you’re interested in growing Cusick’s fumewort, please only source it from reputable native plant nurseries that propagate rather than wild-collect their plants. Never dig plants from the wild, as this can harm already vulnerable populations.

The Mystery of Growing Cusick’s Fumewort

Here’s the honest truth: specific growing information for Cusick’s fumewort is surprisingly scarce. What we do know is that it’s a forb, meaning it’s an herbaceous plant that dies back to ground level and regrows from underground structures each year.

Given its native range in Idaho and Oregon, we can make some educated guesses about its preferences:

  • Likely adapted to the climate conditions of the Pacific Northwest
  • Probably prefers well-draining soils typical of its native habitat
  • May benefit from some protection during extreme weather
  • As a native plant, likely requires minimal fertilization once established

Garden Design Potential

While specific information about Cusick’s fumewort’s garden role is limited, native forbs like this one typically work beautifully in:

  • Native plant gardens that celebrate regional flora
  • Naturalized areas where wildflowers can spread and self-seed
  • Rock gardens or areas with good drainage
  • Wildlife-friendly landscapes (though specific pollinator benefits are unknown)

The Bottom Line for Gardeners

Cusick’s fumewort represents both an opportunity and a responsibility. As gardeners, we have the chance to grow and preserve this native species, but we must do so thoughtfully. Its rarity status means every garden specimen could contribute to conservation efforts – but only if we source plants responsibly.

If you can’t locate Cusick’s fumewort from ethical sources, consider exploring other native Corydalis species or similar native forbs from your region. Your local native plant society or extension office can point you toward abundant native alternatives that will provide similar ecological benefits without conservation concerns.

Remember, the best native garden is one that supports both local ecosystems and plant conservation – sometimes that means choosing more common natives over rare ones, and that’s perfectly okay!

Cusick’s Fumewort

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Magnoliidae

Order

Papaverales

Family

Fumariaceae Marquis - Fumitory family

Genus

Corydalis DC. - fumewort

Species

Corydalis caseana A. Gray - Sierra fumewort

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