Silphium trifoliatum

When whorled rosinweed is in bloom upon the landscape, a layer of sunny flowerheads marks the transition from meadow to sky. At the center of each flowerhead, tubular florets draw in long-tongued pollinators like bumble bees and butterflies. The plant’s leaves encircle its tall stem, creating an attractive look even when the plant isn't in flower.

One of the more easterly distributed members of the silphium genus, whorled rosinweed is tolerant of light shade in addition to full sun, and it occupies woodland openings as well as meadows. If growing at the edge of a tree canopy, however, the plant has a tendency to lean toward the sun. In sunny situations, whorled rosinweed may have difficulty supporting itself during its first growing season, but will be more upright in subsequent years.

Whorled rosinweed grows well in soil moisture ranging from moderately wet to moderately dry, forming small colonies through the production of short underground stems. In overly dry soil, the plant will persist but its flowers will be smaller and less impressive. Attaining a mature height of 5 – 8’, this plant is a long-lived perennial that reliably blooms in midsummer year after year.

References: 1,2,3,4,5.

Photo 1 © Elias, CC0 1.0. Photo 2 by Julie Slater.