Silphium Perfoliatum (Cup Plant) Standing tall at around six feet (more in wetter soils, less in drier soils), Cup Plant's yellow blossoms can be seen starting in July when the butterflies visit them, and then later when the birds begin to feed on its seeds. Throughout the growing season, the water held in the leaf cups attract birds and other critters looking for a drink. Cup Plant establishes well in average garden soil or in heavier, wetter soils. This plant would not be a good choice for small garden as it could overwhelm smaller plants- truly a massive plant. As the specific epithet "perfoliatum" suggests, each pair of leaves clasp the stem, making it look like the stem has pierced through them. The leaves themselves form a small basin that allows rain water to collect in tiny pools around the stem, hence the cup comparison. 7 gal

Cup Plant

  • Full to mostly sun