Thistle Rosette Identification - Biennials (rosette first year and flowering plant the second year).
Nonnative Invasive Thistles Native Thistles
Bull Thistle Rosette Musk Thistle Rosette Anderson’s Thistle Rosette Elk Thistle Rosette
Rosette Shape - more round. Rosette Shape - more round. Rosette Shape - not very round. Rosette Shape - more round.
Leaves in general - rough, Leaves in general - smooth and Leaves in general - dark green Leaves in general - appear light bumpy appearance giving it succulent looking especially and stiff. green and delicate. a duller color and prominent when young. veins. Rosette Leaves Above: Rosette Leaves Above: Rosette Leaves Above: Rosette Leaves Above: 1. Hairs - few long hairs above 1. Hairs - Many long whitish, 1. Hairs above - sandpapery texture 1. No hairs on leaves, smooth 2. Smooth appearance. golden hairs. from small hairs running in one appearance. 2. Long fine spines at leaf margins. direction. 2. Whitish margins. 2. Some long downy hairs along 3. Light green mid-rib. midrib and leaf. Rosette Leaves Below: Rosette Leaves Below: 1. Small flat hairs below and 1. Sometimes small flat hairs on Rosette Leaves Below: Rosette Leaves Below: appears white. underside and appears white. 1. Many hairs in all directions 1. No hairs - lighter green than (tomentose, cobywebby). above. 2. Appears white - from hairs. 3. Prominently raised mid-rib. Thistle Mature Plant Identification - Biennials (rosette first year and flowering plant the second year).
Nonnative Invasive Thistles Native Thistles
Bull Thistle Musk Thistle Anderson’s Thistle Elk Thistle
Flower Color - pink to purple Flower Color - deep pink to Flower Color - rose red to Flower Color - cream, white to purple redish purple pale lavender
Flower Shape - Flower Shape - Flower Shape - vase-shaped disk-shaped cylinder-shaped and typically nods at end of bent naked stem.
Stems - spiny wings Lower Stems - spiny wings Stems - no spines Stemless Thistle Upper Stems - naked
In general more delicate looking with fewer flowers per stem.