Silphium perfoliatum- Cup Plant

Cup Plant is so named because its opposite leaves fuse at the stem to form a cup-like shape that holds water, attracting birds and other small fauna all season long. Its sturdy, upright stems are hairless and square (unique among silphiums), and unbranched until the top, where multiple floral stalks bear bright yellow, 3in sunflower-like flowers. Pollinators visit these blooms all summer long and then goldfinches and other songbirds flock to eat the seeds in the fall. The only silphium that thrives in wet soil, it will be shorter in drier soils. Their especially long taproot makes them long-lived and drought-resistant once established, but also uninterested in being transplanted. Spreads via rhizome such that it is considered aggressive and should be reserved for large garden spaces. Sun: Full, Partial Soil: Medium-Wet, Medium Bloom Time: July, August, September Color: Yellow Height: 8 ft