North America Native Plant

Tracy’s Thistle

Botanical name: Cirsium undulatum var. tracyi

USDA symbol: CIUNT

Life cycle: biennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Carduus tracyi Rydb. (CATR14)  âš˜  Cirsium acuatum (Osterh.) Petr. (CIAC4)  âš˜  Cirsium floccosum (Rydb.) Petr. (CIFL3)  âš˜  Cirsium tracyi (Rydb.) Petr. (CITR4)   

Tracy’s Thistle: A Native Wildflower for Western Gardens If you’re looking to add some authentic western character to your native plant garden, Tracy’s thistle (Cirsium undulatum var. tracyi) might just be the spiky surprise you’ve been searching for. This lesser-known native wildflower brings both beauty and ecological value to the ...

Tracy’s Thistle: A Native Wildflower for Western Gardens

If you’re looking to add some authentic western character to your native plant garden, Tracy’s thistle (Cirsium undulatum var. tracyi) might just be the spiky surprise you’ve been searching for. This lesser-known native wildflower brings both beauty and ecological value to the right landscape setting.

What is Tracy’s Thistle?

Tracy’s thistle is a native forb—essentially a non-woody flowering plant—that calls the American West home. As a biennial or perennial plant, it establishes itself over time rather than racing through a single growing season. You might also see it listed under several historical names in older gardening references, including Carduus tracyi or Cirsium tracyi, but don’t let the botanical name shuffle confuse you—it’s all the same distinctive plant.

Where Does Tracy’s Thistle Grow Naturally?

This thistle has a fairly limited native range, naturally occurring in Colorado and Utah. It’s perfectly adapted to the challenging growing conditions of the American West, making it a true regional specialist rather than a widespread wanderer.

Garden Appeal and Landscape Role

While detailed information about Tracy’s thistle’s specific appearance and growth habits is limited in available resources, thistles in the Cirsium genus typically offer unique architectural interest with their distinctive spiky foliage and often showy flower heads. As a native forb, Tracy’s thistle would likely serve well in:

  • Native plant gardens focused on regional flora
  • Naturalized meadow or prairie-style landscapes
  • Wildlife habitat gardens
  • Low-maintenance xerophytic (dry-adapted) gardens

Growing Conditions and Care

Tracy’s thistle shows some interesting adaptability when it comes to moisture levels. According to wetland indicators, it’s classified as Facultative Upland across the Arid West, Great Plains, and Western Mountains regions. This means it typically prefers well-drained, non-wetland conditions but can tolerate occasional moisture—a handy trait for gardeners dealing with variable rainfall or irrigation patterns.

As a native of Colorado and Utah, this thistle is likely well-suited to:

  • Full sun exposure
  • Well-draining soils
  • Low to moderate water requirements once established
  • Cool to cold winter conditions typical of higher elevations

Wildlife and Pollinator Benefits

While specific wildlife data for Tracy’s thistle isn’t readily available, native thistles generally serve as valuable resources for pollinators. The flower heads typically attract bees, butterflies, and other beneficial insects, while the seeds often provide food for birds, particularly finches who have a special fondness for thistle seeds.

Important Considerations for Gardeners

Before adding Tracy’s thistle to your garden wish list, there are a few things to keep in mind:

  • Limited availability: As a regionally specific native with a small natural range, Tracy’s thistle may be challenging to source from typical nurseries
  • Research gap: Specific growing requirements, mature size, and care needs aren’t well-documented in popular gardening resources
  • Thistle characteristics: Like other thistles, this plant likely has spiny foliage that requires careful placement away from high-traffic areas

The Bottom Line

Tracy’s thistle represents an intriguing opportunity for dedicated native plant enthusiasts, particularly those gardening in Colorado or Utah. While detailed growing information is limited, its native status and regional specificity make it a potentially valuable addition to authentic western native plant collections.

If you’re interested in growing Tracy’s thistle, your best bet is connecting with native plant societies, botanical gardens, or specialized native plant nurseries in Colorado or Utah. These sources can provide both properly sourced plant material and region-specific growing advice that general gardening resources simply can’t match.

For gardeners outside its native range or those seeking similar but better-documented alternatives, consider exploring other native Cirsium species appropriate to your specific region. Your local native plant society can help you identify the thistle species that naturally call your area home.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Arid West

FACU

Facultative Upland - Plants with this status usually occurs in non-wetlands but may occur in wetlands

Great Plains

FACU

Facultative Upland - Plants with this status usually occurs in non-wetlands but may occur in wetlands

Western Mountains, Valleys, and Coast

FACU

Facultative Upland - Plants with this status usually occurs in non-wetlands but may occur in wetlands

Tracy’s Thistle

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Cirsium Mill. - thistle

Species

Cirsium undulatum (Nutt.) Spreng. - wavyleaf thistle

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