North America Non-native Plant

Pasture Knapweed

Botanical name: Centaurea bovina

USDA symbol: CEBO

Life cycle: biennial

Habit: forb

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Pasture Knapweed: An Uncommon European Introduction If you’ve stumbled across the name pasture knapweed (Centaurea bovina), you’re likely dealing with one of the lesser-known members of the knapweed family. This biennial forb represents just one piece of the complex puzzle that is North American plant introductions, and frankly, it’s not ...

Pasture Knapweed: An Uncommon European Introduction

If you’ve stumbled across the name pasture knapweed (Centaurea bovina), you’re likely dealing with one of the lesser-known members of the knapweed family. This biennial forb represents just one piece of the complex puzzle that is North American plant introductions, and frankly, it’s not one you’ll find at your local garden center anytime soon.

What Exactly Is Pasture Knapweed?

Pasture knapweed is a European native that somehow made its way across the Atlantic and decided to set up shop in North America. As a biennial, it follows the classic two-year life cycle: spend the first year building up energy in a low rosette, then burst into flowering glory in year two before calling it quits.

Like other members of the knapweed clan, this plant is classified as a forb—essentially a non-woody herbaceous plant that lacks the substantial woody tissue you’d find in shrubs or trees. Think of it as the middle ground between grasses and woody plants.

Where You’ll Find It (Or Won’t)

Here’s where things get interesting: pasture knapweed has an extremely limited presence in North America, with confirmed populations only in Massachusetts. This makes it something of an oddball in the knapweed world, where its cousins have spread far and wide across the continent.

Should You Plant Pasture Knapweed?

The short answer? Probably not, and here’s why. While this particular knapweed species isn’t currently flagged as invasive or noxious, it’s still a non-native plant with very limited ecological value for our native wildlife. Plus, tracking down seeds or plants would be nearly impossible given its rarity in cultivation.

Better Native Alternatives

Instead of hunting for this European transplant, consider these native alternatives that offer similar aesthetic appeal and much greater ecological benefits:

  • New England Aster (Symphyotrichum novae-angliae) – Purple blooms that pollinators absolutely adore
  • Wild Bergamot (Monarda fistulosa) – Fragrant flowers that attract bees, butterflies, and hummingbirds
  • Purple Coneflower (Echinacea purpurea) – Sturdy, drought-tolerant with seeds that feed birds
  • Spotted Joe-Pye Weed (Eutrochium maculatum) – Tall, showy, and a magnet for butterflies

The Bottom Line

While pasture knapweed isn’t necessarily harmful, it’s not particularly helpful either. In a world where we’re trying to support declining pollinator populations and restore native ecosystems, your garden space is precious real estate. Why not fill it with plants that have co-evolved with our local wildlife and provide food, shelter, and nesting materials for the creatures that call your area home?

If you’re passionate about knapweed-type flowers, stick with the native alternatives mentioned above. They’ll give you beautiful blooms while supporting the intricate web of life that makes our gardens truly come alive. After all, the best gardens aren’t just pretty to look at—they’re working ecosystems that benefit everything from soil microbes to migrating birds.

Pasture Knapweed

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

Centaurea L. - knapweed

Species

Centaurea bovina Velen. - pasture knapweed

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