Meadow Knapweed

Description

Meadow knapweed belongs to the Sunflower family. This plant is native to Europe and was thought to be introduced to North America as a contaminant in alfalfa seed (Ball et al 2006). Meadow knapweed can grow up to one metre tall. It has lance-shaped basal leaves. Several large purple-pink flower heads form at the top of its branched, hairy, erect stems. This species of knapweed is considered to be a hybrid between brown and black knapweed and is often confused with those knapweed species as well as Spotted knapweed. Meadow knapweed reproduces solely by seed (Ball et al 2006).

Type

Perennial Forb

Habitat & Impacts

Meadow knapweed has been known to invade rangelands and pastures, reducing carrying capacities and yields (Ministry of Agriculture, Lands, and Fisheries, 2002).

Method of Spread

Meadow knapweed reproduces primarily through seed however it can re-grow from root and crown fragments. Seeds germinate throughout the growing season and plants typically flower from May to July. The seed is spread via humans, wind, and animals and can remain viable in the soil for several years.

Location

Occurs in the Bella Coola Valley along the Tote road (currently unmapped), and outside the CCCIPC area along HWY 97 approx. 0.5km north of Loch Lomond in the TNRD and possibly north of Lac Des Roches (not confirmed).

Mechanical

Seed production can be reduced by mowing and hand pulling plants prior to flowering and seed production.

Chemical

Picloram, dicamba, or a combination of clopyralid and 2,4-D are a few of the herbicides that effectively control Meadow knapweed. (Ministry of Agriculture, Lands, and Fisheries, 2002).

Biological

Several biological control agents are used to control Meadow knapweed. These include Larinus obtusus (seed feeding weevil), Metzneria paucipunctella (seed feeding moth) and Urophora quadrifasciata (seed feeding fly) (Ministry of Forests and Range, 2007).

CCCIPC Priority & Treatment Strategy

Priority 1 (new invader)

Local Level

Frequently mowing and hand pulling small infestations.

Landscape Level

Chemical control and possible biological control for larger infestations.