Family: Asteraceae (Sunflower family)
Duration: Perennial
Height: 1-2.5 m (3-8 ft)
Blooming: July-Sept.
Cup Plant
Silphium perfoliatum L.
Stem: thick and squared.
Flowers: large yellow flower-heads up to 4 inches in diameter.
Leaves: The leaves are large and opposite joining around the stem making a cup that holds water. The leaves have large teeth and have a rough texture.
Sun: Full to part sun
SOURCES & FURTHER RESOURCES:
Flora of North America - Silphium perfoliatum
Illinois Wildflowers - Cup plant
Comments: The common name comes from the cup around the stem that is created by the joining of the opposite leaves. It grows new plants rhizomatous creating a dense stand of large plants. It grows in wetter soil than its sister silphiums. Unlike compass plant (S. laciniatum) and prairie dock (S. terebinthinaceum), the leaves of cup plant are oppositely arranged. It differs from rosinweed (S. integrifolium) by fully clasping around definite four sided stems whereas rosinweed slightly holds on to a round stem.
Etymology: The genus, Silphium, comes from the Greek name for a mythic resinous plant called Silphion. The specific epithet, perfoliatum, comes from two Latin words combined to mean "through the leaf" which relates to the stem protruding through the leaves.
Butterfly/moth host plant: Silphium borer moth (Tabenna silphiella)
all photos by Nathanael Pilla
Landscape: a great plant for the area in your landscape that needs a tall, showy perennial. It is a great addition to a corner planting that can be overtaken by a large, gorgeous plant. Carpenter bees make homes in the past vegetative stands. Birds love this plant for water, food, and shelter.
