Thistle – Scotch

Scientific Name: Onopordum acanthium

Family: Asteraceae

Structure: Erect, up to 8 feet tall with branching, spiny leaf wings that extend down onto the stem and are covered with dense fine hairs.

Life Cycle: Rosette forms first year; flowering stem elongates second year.

Leaves: Large, coarsely lobed, hairy on both sides, velvety-gray appearance. Margins are lined with sharp spines. Basal leaves up to 2 feet long and 1 foot wide.

Flowers: Violet to reddish colored, 1–2 inches in diameter, solitary, terminal with spine-tipped bracts.

Roots: Large fleshy taproot.

Treatment:

Application Timing: Apply in the spring and early summer to rosette or bolting plants or in the fall to seedlings and rosettes before ground is frozen. Use higher rates after bolting through early flower.

Recommendation:
5 to 7 fluid ounces of Milestone^® herbicide per acre, or for broader-spectrum weed control, apply 1.2 to 1.5 pints of ForeFront^® HL herbicide per acre. Apply when weeds are actively growing and under conditions favorable for plant growth.