Silphium integrifolium

Silphium integrifolium, commonly called rosinweed or whole-leaf rosinweed, grows in prairies, glades, railroad right-of-ways, and roadsides in the Midwest and southern states. Silphiums typically grow 2-3 feet tall, though they can grow up to 6 feet tall. Leaves are medium green, with smooth or finely serrated margins, on the erect, hairy stems. There is a wide variety of leaf shapes, from lanceolate to ovate to elliptic. Mid-summer brings corymb-like inflorescences with flowers resembling small sunflowers. Each flower has yellow rays and a yellow disk in the center. There is a reflexed tip on the bracts that cover the flowers.

A well-drained, medium moisture soil in full sun is ideal for growing this plant. It tolerates some light shade. Once established, it can also tolerate some drought. Various soils can be used, including sandy, loamy, and clay soils. The establishment of plants in the garden can be slow, particularly when they are grown from seed. In optimum growing conditions, plants often self-seed. As plants grow, they develop taproots. Once established, the division is not recommended.

BONAP MAP

Height: 2’-6’
Spread: 1’-3’
Bloom: July-September
Light: Full Sun
Water: Medium
Zone: 4, 5, 6, 7, 8
Origin: Central North America
Deer Resistant: No