Cup plant
Silphium perfoliatum
Silphium perfoliatum
Sun/shade: Full sun
Soil moisture: Medium to wet
Height: 4-8'
Spread: 1-3'
Flowering period: August
Few plants can rival the dramatic architecture of cup plant, whose large, concave leaves capture rainwater to form a series of pools along a central, towering stem. The pools present a rare form of wildlife value, serving as a water source for birds, pollinators, and other organisms. In mid to late summer, a crown of yellow flowers provides a beautiful complement to a backdrop of blue skies. The pollinator value of the plant’s flowers is such that the Xerces society has selected cup plant for its short list of recommended pollinator plants for the Great Lakes region. After the growing season is over, cup plant’s hollow stem continues to serve as nesting habitat for leafcutter bees.
Native to NE Ohio habitats including wet meadows, woodland edges, and the margins of water bodies, cup plant grows well under conditions of wet to average soil moisture and full sun to partial shade. In keeping with its imposing stature (up to 10’ tall), cup plant can be quite dominant, frequently forming colonies through growing via numerous rhizomes. If intermingled with other plants as a mixed planting in the garden, cup plant may take over. It thus may be best to plant cup plant in a discrete patch that is spaced apart from other plants.
Photos by Alyssa Zearley.