Plant of the Week
Cut-leaf Prairie-Dock (Silphium pinnatifidum)
By Robert Arndt
Cut-leaf Prairie-dock, also known as tansy rosinweed, has been reported to occur from Wisconsin south through Illinois, Ohio and Indiana, through Kentucky and Tennessee and into Georgia and Alabama. It can be found associated with Prairie Gentian (Gentiana puberlenta), Leafy Prairie Clover (Dalea foliosa), Fewleaf Sunflower (Helianthus occidentalis), Pale Purple Coneflower (Echinacea simulata), Barrelhead Gayfeather (Liatris cylindracea), Little Bluestem (Schizachyrium scoparium), Tennessee Coneflower (Echinacea tennesseensis), and White Prairie Clover (Dalea candida) (Molano-Flores).
This native species is uncommon and has leaves arranged in a basket-sized rosette pattern, each of which can reach 2 ½ feet long and 1 foot wide (Barnes and Francis). A flowering stalk is produced by each rosette that is smooth, practically leafless, and can reach 10 foot or more in height. Each stalk terminates in a saucer-sized yellow flower that is similar to a sunflower except it has with a yellow center, unlike the dark center of sunflowers (Chester and Ellis).
This sunflower-resembling species flowers in mid-summer to early fall and can be found growing in prairie patches and glades (Barnes and Francis). It has also been reported to grow on dry roadsides, such as Silver Trail and The Trace in Land Between the Lakes NRA (Chester and Ellis).
- Barnes, T.G. and S.W. Francis. 2004. Wildflowers and Ferns of Kentucky. The University Press of Kentucky, Louisville, Kentucky.
- Chester, E.W. and W.H. Ellis. 2000. Wildflowers of the Land Between The Lakes Region, Kentucky and Tennessee. Second Edition. The Center for Field Biology, Austin Peay State University, Clarksville, Tennessee.
- Molano-Flores, Brenda. 2004. Conservation Assessment for Prairie-Dock (Silphium pinnatifidum Elliot). United States Forest Service, Eastern Region.