Species Native to Missouri
Common Name: cup plant
Type: Herbaceous perennial
Family: Asteraceae
Native Range: Central-eastern Canada to southeastern United States
Zone: 3 to 9
Height: 4.00 to 8.00 feet
Spread: 1.00 to 3.00 feet
Bloom Time: July to September
Bloom Description: Yellow
Sun: Full sun
Water: Medium to wet
Maintenance: Low
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Attracts: Birds, Butterflies
Tolerate: Clay Soil, Wet Soil
Culture
Easily grown in average, medium to wet soils in full sun. Prefers moist, rich soils, but tolerates some drought once established. Somewhat slow to establish when grown from seed. Self-seeds in optimum growing conditions.
Noteworthy Characteristics
Silphium perfoliatum, commonly called cup plant, is a coarse, sunflower-like, Missouri native plant which occurs in open, low woods and thickets, wet meadows and prairies, stream/pond peripheries and along railroad tracks in the Midwest and portions of the southern United States. It typically grows on tough, erect stems to 4-8' tall and is distinguished from the other silphiums by its square/quadrangular stems and pairs of cup-forming leaves. Flower heads (to 3" diameter) featuring light yellow rays (20-40) and darker yellow center disks bloom in summer on the upper part of the plant. Rough, triangular to ovate, coarsely-toothed, opposite, connate-perfoliate, medium green leaves can reach 14" long. The leaf pairs are united at their bases, enveloping the stems.
The genus name Silphium comes from the Greek name silphion, used to refer to a resin-bearing plant from northern Africa.
Specific epithet means having leaves that surround the stem.
Problems
No serious insect or disease problems.
Uses
A large plant that needs lots of space. Some gardeners find cup plant to be too large and weedy for border rears, but others find it to be an effective backdrop for other perennials. Adapts well to prairies, wildflower/native plant gardens, naturalized areas or moist, open woodland areas including stream/pond edges.