North America Non-native Plant

Singleflower Knapweed

Botanical name: Centaurea uniflora nervosa

USDA symbol: CEUNN

Life cycle: perennial

Habit: forb

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

Synonyms: Centaurea nervosa Willd. (CENE2)   

Singleflower Knapweed: A Lesser-Known Perennial with Limited Garden Information If you’ve stumbled across the name singleflower knapweed in your plant research, you’re dealing with one of those botanical mysteries that keeps gardeners scratching their heads. Scientifically known as Centaurea uniflora nervosa, this perennial forb is part of the vast Centaurea ...

Singleflower Knapweed: A Lesser-Known Perennial with Limited Garden Information

If you’ve stumbled across the name singleflower knapweed in your plant research, you’re dealing with one of those botanical mysteries that keeps gardeners scratching their heads. Scientifically known as Centaurea uniflora nervosa, this perennial forb is part of the vast Centaurea family, but information about this particular variety is surprisingly scarce in gardening circles.

What We Know About Singleflower Knapweed

Singleflower knapweed is classified as a perennial forb, which means it’s an herbaceous plant that lacks woody stems and returns year after year. Like other forbs, it produces its growing buds at or below ground level, helping it survive harsh weather conditions. This plant is also known by the synonym Centaurea nervosa Willd., though you’re unlikely to find it under either name at your local nursery.

Where Does It Grow?

Currently, Centaurea uniflora nervosa has been documented in New York state, though its exact distribution and habitat preferences remain unclear. As a non-native species that has been introduced to North America, it represents one of many plants that have found their way into our ecosystems through various means.

The Garden Reality Check

Here’s where things get tricky for gardeners: there’s very little practical information available about growing singleflower knapweed. We don’t have clear data on its:

  • Preferred growing conditions
  • Size at maturity
  • Flower characteristics
  • Care requirements
  • Hardiness zones
  • Wildlife benefits

This lack of information suggests that Centaurea uniflora nervosa isn’t commonly cultivated or widely studied, making it a poor choice for most garden applications.

Consider Native Alternatives Instead

Since singleflower knapweed is non-native and offers unclear benefits to your garden ecosystem, why not explore native alternatives that provide guaranteed value? Native plants in the aster family (which includes many Centaurea relatives) offer excellent options:

  • Native asters provide late-season blooms and support local pollinators
  • Wild bergamot attracts butterflies and hummingbirds
  • Purple coneflower offers stunning flowers and feeds birds
  • New England aster provides fall color and pollinator habitat

The Bottom Line

While Centaurea uniflora nervosa might sound intriguing, the lack of available growing information and its non-native status make it a questionable garden choice. Your time and garden space are better invested in well-documented native plants that support local ecosystems and provide predictable results.

If you’re specifically interested in the Centaurea genus, consider researching native alternatives in your region, or consult with local native plant societies who can guide you toward similar plants that truly belong in your local landscape. After all, the best gardens are those that work with nature, not against it.

Singleflower 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 uniflora Turra - singleflower knapweed

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