The Cup Plant, known in Latin as Silphium perfoliatum towers nearly 12 feet tall at the back of the herbaceous border. It is so named because the large triangular leaves are perforated by the stem, forming a cup in which water collects for the benefit of insects and other forms of wildlife in the garden.
Almost as tall is the Whorled Rosinweed, Silphium trifoliatum. This plant is named for the whorl of three leaves (trifoliate) that circle the stem.
It was first described by the eminent Virginia botanist, John Clayton, Clerk of Court for Gloucester County and author of Flora Virginica printed in Leiden, Holland by Gronovius and heavily relied upon by Carlous Linnaeus in his groundbreaking work Species Panatarum published in 1753.
While it is true that the foliage is usually composed of whorls of three, there are also examples of plants that carry their leaves in whorls of four which Mr. Clayton must have encountered.
To support these giant plants from blowing down during summer storms we have devised a support made of stakes that are sharpened and driven into the ground with a lattice of grape vines laid over them and nailed in place.
The plants grow up through the vines and are thus supported in blustery weather.