meadow knapweed Centaureax moncktonii C. E. Britton[C. jacea X C. nigra]
Appearance
Centaurea x moncktonii is an herbaceous, perennial weed, living 3-5 years on average. It is a fertile hybrid between brownray knapweed and lesser knapweed. It is usually bushy with erect stiff branches and grow from 1-4 ft (0.3-1.22 m) tall. It is native to Europe. It has been found across the United States and Canada.
Foliage
Leaves are up to 6 in. (15.2 cm) long and 1 in. (2.5 cm) wide and decrease in size as they move up the stem. The lower leaves are toothed or lobed and the upper leaves are linear.
Flowers
Flowering occurs in May to August, sometimes later if it is mowed. Flowers are pink to purple, contained in heads and located at the tips of the branches. Each is about the size of a nickel and much rounder than spotted knapweed flower heads. Bracts around the flower head are light to dark brown, with a thin fringed margin. The bracts look shiny and coppery once the flowers are mature.
Fruit
The plant reproduces by seed and is shed immediately one it is mature. Seed production is prolific with from 1,000-25,000 seed per plant a year. Seed can survive in the soil seed bank for over five years.
Ecological Threat
Caution: All Centaurea spp. contain carcinogens, always wear gloves and use caution when handling these plants.Centaurea x moncktonii grows best along moist roadsides, sand/gravel bars and river banks, irrigated pastures, moist meadows, and forest openings.