Plant of the Week: Prairie Dock

highlighted mobile

Author: 
Adam Dooling
Prairie dock on the High LinePrairie dock, Silphium terebinthinaceum, can reach 10 feet in height. Photo by Friends of the High Line

The High Line’s planting design is inspired by the self-seeded landscape that grew up between rail tracks after the trains stopped running in the 1980s. Today, the High Line includes more than 300 species of perennials, grasses, shrubs, and trees – each chosen for their hardiness, adaptability, diversity, and seasonal variation in color and texture. Some of the species that originally grew on the High Line’s rail bed are reflected in the park landscape today.

This week we share one of our gardeners’ current favorites with you.

Towering above the native grasses and wildflowers of the Chelsea Grasslands is Silphium terebinthinaceum – the prairie dock. The scale and architecture of this plant are breathtaking, giving it an almost prehistoric appearance. An enormous basal rosette appears in spring, eventually giving way to stark and soaring branched panicles of yellow flowers. These corymbs can reach upwards of 10 feet in height and will sustain interest year-round.

It is the primitive look of S. terebinthinaceum that partially inspired garden pioneer William Robinson to write his seminal treatise The Wild Garden, a book that would revolutionize gardening in the late 19th century. This work marked the movement to a more naturalistic style of gardening, and many of Robinson’s ideas remain relevant to this day.

The prairie dock’s common name alludes to its resemblance to the species dock (rumex). Like rumex, the prairie dock sends out an enormous tap root which makes it extremely drought resistant, but slow to establish and difficult to transplant. Apart from this, the two plants share little in common with each other, and it is the origin of the scientific name Silphium terebinthinaceum that may be of greater interest to the reader.

While the Greek terebinthinaceum means "like turpentine" – in reference to scented resins similar to that of the terebinth tree – the genus name Silphium derives from silphion, an extinct species of North African plant integral to many ancient Mediterranean cultures. The plant’s resinous and medicinal qualities were widely known, and some legends lauded it as a gift from Apollo himself. This cultural importance was evidenced by depictions of silphion on the coinage of the ancient city of Cyrene, where the plant was said to grow exclusively. It is very likely that the image of a silphion seed, strikingly similar to that of the Egyptian Ib, is the origin of the modern heart symbol. Sadly, the plant proved to be impossible to cultivate, and over-harvesting is believed to have led to its extinction. This story can be cited as one of the earliest arguments for a sustainable agricultural practice.

WHERE TO SEE THIS PLANT
Silphium terebinthinaceum can be found on the High Line in the Chelsea Grasslands between west 18th and 20th streets.

Download our November Bloom Guide.