Cup Plant
Silphium perfoliatum · Herbaceous Perennial (Not a true tree)
Plant Family
Asteraceae
Tree Category
Forb/Flowering Native Perennial
Variety / Cultivar
None (Wild type)
Hardiness Zones
USDA Zones 3 through 9.
About This Tree
While often mistaken for a young tree due to its massive size, this is a tall herbaceous perennial. It has a sturdy, square, upright stem that can reach significant heights, supporting large, coarse foliage and sunflower-like yellow blooms.
Leaf Characteristics
Opposite, simple, large (up to 12 inches long), triangular to ovate with coarsely toothed margins. The leaf bases are fused around the stem, forming a 'cup' that collects rainwater.
Bark Characteristics
Not applicable (Herbaceous); the stem is distinctly square (four-sided), light green to reddish-purple, and smooth but sturdy.
Growing Information
Origin Region
Native to Central and Eastern North America, spanning from Ontario to Georgia and west to the Great Plains.
Growing Season
Active growth begins in mid-spring; flowers bloom from July to September; enters dormancy after the first hard frost.
Sunlight & Water Needs
Prefers full sun to partial shade. Requires moist to mesic soil; enjoys wet prairies and pond edges but is drought-tolerant once established.
Mature Size
Height: 4 to 8 feet (sometimes taller); Spread: 2 to 3 feet; Growth Rate: Fast during the summer season; Lifespan: Perennial (many years).
Special Characteristics
Resistant to most pests/diseases; unique 'cup' leaves provide water for birds; excellent for erosion control in rain gardens; high drought and heat tolerance.
Wildlife & Ecology
Highly valuable ecological plant. The 'cups' provide a water source for birds and insects. Flowers attract honeybees, bumblebees, and butterflies. Seeds are a favorite of goldfinches.