Silphium perfoliatum or the Cup Plant is native to North America. It is also called the Cup Rosin Weed or Indian Cup. It grows rather tall, up to 2 meters or 6ft tall. It is a herbaceous perennial that produces daisy-like yellow flowers in mid to late summer. It is part of the Asteraceae family of plants.
Silphium perfoliatum stems are glabrous or hairy. The foliage is ovate, opposite, and toothed. They are joined around the stem. The first flowers grow on the main stems and then the branched ones. The flowers are like sunflowers. They are about 2.5cm or 1in in diameter. It has yellow florets surrounding sterile, tubular disk flowers. The plants are bisexual but only stamens are fertile.
Grow Silphium perfoliatum in the sun or partial shade. Plant it in moist but well-drained soil. It is easy to grow and you can propagate by seeds or division. You may need to stake to support if you plant them in a windy location. Silphium perfoliatum is generally disease-free and pest-free.