North America Non-native Plant

Meadow Knapweed

Botanical name: Centaurea ×moncktonii

USDA symbol: CEMO6

Life cycle: perennial

Habit: forb

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

Meadow Knapweed: A Mysterious Hybrid Worth Reconsidering If you’ve stumbled across the name meadow knapweed or Centaurea ×moncktonii in your gardening research, you might be scratching your head trying to find reliable information about this plant. Don’t worry – you’re not alone! This particular species is something of an enigma ...

Meadow Knapweed: A Mysterious Hybrid Worth Reconsidering

If you’ve stumbled across the name meadow knapweed or Centaurea ×moncktonii in your gardening research, you might be scratching your head trying to find reliable information about this plant. Don’t worry – you’re not alone! This particular species is something of an enigma in the gardening world, and there’s a good reason why detailed growing guides are hard to come by.

What is Meadow Knapweed?

Meadow knapweed (Centaurea ×moncktonii) is a perennial hybrid plant, indicated by the × symbol in its scientific name. It belongs to the knapweed family and grows as a forb – essentially a non-woody herbaceous plant that lacks significant woody tissue above ground. Like other forbs, it develops perennating buds at or below ground level that help it survive through seasons.

Where Does It Grow?

This non-native species has established itself across several regions in North America, including:

  • Canadian provinces: British Columbia, Nova Scotia, Ontario, and Quebec
  • U.S. states: Connecticut, Massachusetts, New York, and North Carolina

The plant has managed to reproduce spontaneously in the wild without human intervention and tends to persist in these areas once established.

Growing Conditions and Habitat Preferences

Based on wetland indicator status data, meadow knapweed shows remarkable adaptability across different regions:

  • In most areas, it prefers upland conditions but can tolerate some wetland environments
  • In coastal regions and western mountains, it’s equally comfortable in both wetland and non-wetland settings
  • This flexibility suggests it’s quite adaptable to various soil moisture conditions

The Problem with Limited Information

Here’s where things get tricky: despite its presence across multiple regions, reliable detailed information about Centaurea ×moncktonii’s specific growing requirements, wildlife benefits, and ecological impact is surprisingly scarce. This lack of comprehensive data raises some red flags for gardeners.

When a plant species has limited research backing and belongs to a genus known for producing invasive species, it’s often wise to proceed with caution – or better yet, look for well-documented alternatives.

Why You Might Want to Skip This One

While we can’t definitively label this particular hybrid as invasive or noxious (the data simply isn’t available), the knapweed family includes several species that have become problematic invaders in North American ecosystems. Without clear information about:

  • Its specific ecological impact
  • Proper cultivation requirements
  • Wildlife and pollinator benefits
  • Appropriate garden settings

It’s difficult to recommend meadow knapweed as a garden addition.

Better Native Alternatives to Consider

Instead of gambling on this mysterious hybrid, why not choose native plants with well-documented benefits? Depending on your region, consider these alternatives that offer similar herbaceous perennial characteristics:

  • Wild bergamot (Monarda fistulosa) – excellent for pollinators
  • New England aster (Symphyotrichum novae-angliae) – late-season blooms
  • Purple coneflower (Echinacea purpurea) – stunning flowers and seed heads for birds
  • Black-eyed Susan (Rudbeckia species) – cheerful and reliable bloomers

The Bottom Line

Sometimes in gardening, the most responsible choice is to step back and choose plants with clear benefits and well-understood growing requirements. While Centaurea ×moncktonii might seem intriguing, the lack of reliable information combined with its non-native status makes it a questionable choice for most gardens.

Your local native plant society or extension office can help you identify fantastic native alternatives that will provide beauty, support local wildlife, and give you the confidence that comes with choosing well-researched plants. After all, why take a gamble when there are so many proven native options waiting to shine in your garden?

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

Atlantic and Gulf Coastal Plain

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

Eastern Mountains and Piedmont

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

Great Plains

FACU

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

Midwest

FACU

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

Northcentral & Northeast

FACU

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

Western Mountains, Valleys, and Coast

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

Meadow 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 ×moncktonii C.E. Britton [jacea × nigra] - meadow knapweed

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