A biennial or occasionally perennial that forms a basal rosette during the first year of growth and produces a flowering stem during the second year.  Spotted knapweed is primarily a weed of pastures, hayfields, roadsides, and sometimes turfgrass

Seedling:  Cotyledons round at the apex and narrowing to the base.  The first true leaves are similar but narrow to a petiole.

Leaves:  Leaves form a basal rosette during the first year of growth, are deeply lobed, and are approximately 6 inches long.  Leaves that are produced on the flowering stems are alternate and finely dissected.  Leaf surfaces often have inconspicuous short hairs but leaf margins have more noticeable tough hairs.

Stems: Flowering stems are slender and wiry, branching, and covered with downy hairs.

Roots:  Taproot

Flowers: Solitary flowers are produced at the ends of branches and are approximately 8 to 15 mm wide.  Individual flowers are pink to purple in color and have a “cone” of bracts below.

Fruit:  An achene that is light green to brown in color and approximately 3 mm long by 2 mm wide.