Silphium perfoliatum

Common Names

Cup Plant, Indian Cup, Cup Rosin Weed, Rosinweed, Carpenter's weed

Summary

Cup Plant, Silphium perfoliatum, is a tall native perennial from central-eastern Canada to the southeastern United States, typically 4–8 ft tall with a 1–3 ft spread. It has square stems and large opposite leaves whose bases clasp the stem to form water-holding cups; yellow flower heads bloom in midsummer to early fall, about 2–3 inches across with 20–40 yellow ray florets around a darker central disk, providing nectar for pollinators and water for birds through the leaf cups. It prefers full sun with moist to wet soils and tolerates clay; it grows easily in average moist conditions and is drought-tolerant once established. It self-seeds prolifically and can be aggressive in some areas; taller growth may require staking in windy sites, and transplanting is easier when plants are young due to an extensive root system. Propagation is by seed or division; it is hardy in USDA zones 3–9. In landscapes it suits back-of-border plantings, prairies, wildflower/native beds, and rain gardens, while supporting wildlife by attracting bees, butterflies, skippers, and birds

Lifecycle

Perennial

Height

4-10 feet

Spread

48-72 inches

Hardiness Zones

Zones 3-9

Sunlight Requirements

Ideally Full Sun; tolerates Partial Sun to Partial Shade.

Soil Type

Moist, well-drained loamy soil

Soil Drainage

Moist, well-drained soil

Soil pH

Tolerates all pH levels

Bloom Color

Yellow

Bloom Time

Summer to Fall

Foliage Color

Medium green

Fall Foliage Color

Yellow

Leaf Lifecycle

Deciduous

Growth Rate

Somewhat slow to establish; takes about 2–5 years to reach its ultimate height.

Seasons of Interest

Spring, Summer, and Fall.

Propagation Methods

Seeds, Division

Attracts Wildlife

Attracts bees, butterflies, other pollinators, and birds