Prairie dock (Silphium terebinthinaceum) is just as desirable for its foliage as it is for its flowers. The plant has huge fan-like basal leaves that are a nice addition to the garden throughout the year, then in late summer sends up clusters of bright yellow flowers on delicate stocks. The flowers are popular with bees and the seeds are eaten by finches and other songbirds. Note prairie dock can grow to be over 8 feet tall and requires adequate space.
Wet and cold stratification required. Mix seeds with moist substrate (vermiculite, perlite or moss) and place in a plastic bag and refrigerate for 6-8 weeks. Sow seed at 1/8 inch depth. Do not let seedling dry out while it is establishing.
Sow directly outdoors in late fall to overwinter.