First-year plants produce a basal rosette, alternate, up to 15 centimetres (6 inches) long, deeply divided into lobes.

The plant grows on stream banks, pond shorelines, sand prairies, old fields and pastures,[citation needed] roadsides, along railroads, and in many open and disturbed areas.

[10] Spotted knapweed is a pioneer species found in recently disturbed sites or openings, growing in dense stands.

It readily establishes itself and quickly expands in places of human disturbance such as industrial sites,[11] along roadsides, and along sandy riverbanks.

[12] This species is believed to have several traits that contribute to its extreme competitive ability:[citation needed] A study conducted in 2003 has shown that with future global atmospheric carbon levels, C. stoebe shows increased growth with increased atmospheric carbon which could potentially expand its range and outcompete native species.

[15] A 1996 study estimated the direct plus secondary economic impact of spotted knapweed in Montana to be approximately $42 million annually.

"[18] The roots of Centaurea stoebe exude (-)-catechin, which has been proposed to function as a natural herbicide that may inhibit competition by a wide range of other plant species.

[23] An 8-year study in Michigan found that restoring native plant communities in knapweed-infested sites requires multi-faceted and multi-year approaches.

This includes an initial site preparation by mowing and an optional application of a clopyralid or glyphosate herbicide followed by reseeding with the desired plant communities.

Burning treatments of infested sites reduced the labour needs for pulling and encouraged native plant community establishment.

[25] Thirteen biological pest control agents have been used against this plant and its congener, diffuse knapweed (C. diffusa), including the moths, Agapeta zoegana and Metzneria paucipunctella; the weevils, Bangasternus fausti, Larinus obtusus, Larinus minutus and Cyphocleonus achates; and the fruit flies, Chaetorellia acrolophi, Urophora affinis and Urophora quadrifasciata.

Previous methods of detection involved lining up dozens of volunteers to locate the small rosettes buried somewhere on a large parcel of land covered with other vegetation.