Virtues: We love the cup plant (Silphium perfoliatum) for its sunny yellow flowers that bloom from midsummer through autumn. This tall, wetland-prairie native tolerates damp soil.
Common name: Cup plant
Botanical name:Silphium perfoliatum
Flowers: Yellow daisy- or sunflower-like flowers to three inches across appear in midsummer and can continue to autumn.
Foliage: Large leaves that can hold water, hence the name cup plant.
Habit: Herbaceous perennial to eight feet tall and three feet wide.
Origin: Wood edges and riverbanks of the eastern half of North America.
Season: Mid to late summer or autumn for its flowers.
How to grow it: Grow cup plant in average garden soil, full sun and with moderate to frequent watering. It tolerates mucky or wet soil, but it also somewhat accepts drought once it is established. May self seed, but seedlings are slow to fully develop. USDA Zones 3–9.