North America Native Plant

Canadian Lousewort

Botanical name: Pedicularis canadensis fluviatilis

USDA symbol: PECAF

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Pedicularis fluviatilis A. Heller (PEFL11)   

Canadian Lousewort: A Rare Native Wildflower Worth Knowing About Meet Canadian lousewort (Pedicularis canadensis fluviatilis), a fascinating native wildflower that’s flying under the radar in most gardening circles. This perennial herb belongs to a unique group of plants that have captivated botanists for generations, though it remains relatively mysterious to ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3T4: Status is uncertain but is somewhere between the following rankings: 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. ⚘ 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. ⚘

Canadian Lousewort: A Rare Native Wildflower Worth Knowing About

Meet Canadian lousewort (Pedicularis canadensis fluviatilis), a fascinating native wildflower that’s flying under the radar in most gardening circles. This perennial herb belongs to a unique group of plants that have captivated botanists for generations, though it remains relatively mysterious to the average gardener.

What Makes Canadian Lousewort Special?

Canadian lousewort is a native perennial forb—basically a soft-stemmed flowering plant without woody tissue. Unlike trees and shrubs that develop thick, woody stems, this plant stays herbaceous throughout its life, with its growing points nestled at or below ground level to survive harsh conditions.

This plant carries some interesting botanical baggage, including the synonym Pedicularis fluviatilis, which gives us a clue about its relationship to water (fluviatilis means of rivers in Latin).

Where You’ll Find It in the Wild

Canadian lousewort has a surprisingly limited native range, calling only Colorado and New Mexico home. This restricted distribution makes it a true regional specialty, adapted to the unique conditions of the American Southwest.

A Rare Plant That Deserves Respect

Here’s where things get interesting—and a bit concerning. Canadian lousewort has a Global Conservation Status of S5T3T4, which indicates it’s considered rare and potentially vulnerable. This rarity status is a red flag for responsible gardeners.

Important: If you’re considering adding this plant to your garden, please source it only from reputable nurseries that can guarantee the plant material was ethically and sustainably obtained. Never collect from wild populations.

Wetland Flexibility

One of Canadian lousewort’s most intriguing characteristics is its flexible relationship with water. Its wetland status varies by region:

  • In the Arid West: Facultative (equally happy in wet or dry conditions)
  • In the Great Plains: Facultative Upland (prefers dry conditions but tolerates some moisture)
  • In Western Mountains: Facultative (adaptable to various moisture levels)

This adaptability suggests a plant that’s learned to make the most of variable water conditions—a valuable trait in our changing climate.

Should You Plant Canadian Lousewort?

The honest answer? Probably not, unless you’re an experienced native plant enthusiast with a specific restoration project in mind. Here’s why:

  • Its rarity means it’s difficult to source responsibly
  • Limited information exists about its cultivation requirements
  • It may have very specific growing needs that are hard to replicate
  • There are many other native alternatives that are easier to grow and more readily available

Better Native Alternatives

If you’re drawn to the idea of native louseworts, consider looking into other Pedicularis species that are more common and better understood horticulturally. Your local native plant society or extension office can recommend suitable alternatives that will give you similar ecological benefits without the ethical concerns.

The Bottom Line

Canadian lousewort represents the fascinating diversity of our native flora, but it’s probably best appreciated in its natural habitat rather than in our home gardens. Sometimes the most responsible thing we can do as gardeners is to admire a plant from afar and choose more sustainable alternatives for our landscapes.

If you do encounter this rare beauty in the wild during your Colorado or New Mexico adventures, take a moment to appreciate its resilience and the unique ecological niche it fills. That might be the most meaningful connection you can make with this elusive native wildflower.

Canadian Lousewort

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Scrophulariales

Family

Scrophulariaceae Juss. - Figwort family

Genus

Pedicularis L. - lousewort

Species

Pedicularis canadensis L. - Canadian lousewort

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