Musk Thistle normally requires 2 years to complete its life cycle (i.e. biennial or winter annual), but occasionally, the plant completes its life cycle in 1 growing season (i.e. summer annual). The typical biennial Musk Thistle exhibits itself the first year in the form of a rosette, a cluster of tightly packed leaves lying flat on the ground.
Rosettes vary in diameter from a few inches to 3 feet. Musk Thistle overwinters as a rosette. During the rosette stage (either fall or spring) Musk Thistle is most susceptible to chemical control.
In its second year of growth, the Musk Thistle plant will leave the rosette stage as its stem elongates (bolts) toward the mature, flowering plant. Chemical control is less effective during the bolted stage and chemical susceptibility continues to decline as the plant reaches maturity.
The leaves of Musk Thistle are deeply lobed (segmented), hairless, and are dark green with a light green mid-rib. A silver-gray leaf margin is characteristic of each spine-tipped lobe. The leaf base extends down the stem to give the plant a winged appearance.
Musk Thistle is the first of the Kansas thistles to bloom in the spring. Flowering begins in mid-May and continues through early July. Each head consists of many tightly packed rose to purple colored flowers encased in a series of spine-tipped, green bracts. The terminal (uppermost) head is 2 - 3 inches in diameter, solitary, and generally bent over or nodding. The mature plant is generally branched, with lower branch producing 1 or more heads. Flowering begins with the terminal head and progresses downward. Musk Thistle heads are distinguished by their "powder puff" shape.
Field bindweed is a perennial that reproduces by seeds and rhizomes. Vines that are many feet long trail over the soil and vegetation and often form dense mats. Leaves alternate along the stem and are attached to it by a short leaf stalk or petiole. Leaf size and shape may vary considerably; typically leaves are up to two inches long and ovate (egg-shaped) with a pair of basal lobes pointing down and/or outward.
Flowers are funnel-shaped, 1-inch in diameter, white to pinkish, and borne singly on a long flower stalk. Two small bracts (appendages) on the flower stalk, 1/2 - 2 inches below the flower, distinguish field bindweed from hedge bindweed.