Silphium terebinthinaceum - NIRPC headquarters.jpg

Family:     Asteraceae (Sunflower family)

Duration:  Perennial

Height:     up to 205 cm (up to 8 ft)

Blooming: July-Sept.

 

Prairie Dock

Silphium terebinthinaceum Jacq.

Stem: rounded and smooth.

Flowers: large yellow flower-heads up to 5-8 cm (2-3 in) in diameter.  

Leaves: large leaves that are basal up to 40 cm (15 in) ​in length predominantly basally arranged. The leaves stand erect kin to large elephant ears.  If the stem has leafs, they are smaller and alternately arranged.

Sun:  Full to part sun

Silphium terebinthinaceum.jpg
Silphium terebinthinaceum-.jpg

Comments:  The variety in Northwest Indiana  has leaf blades that are not lobed. Unlike compass plant (S. laciniatum)  prairie dock's leaves are not lobed and are usually basal. It differs from rosinweed and cup plant by the leaf arrangement as well with both rosinweed and cup plant having oppositely arranged leaves up the stem.

 

Etymology: The genus, Silphium, comes from the Greek name for a mythic resinous plant called Silphion.  The specific epithet, integrifolium, comes from two Latin words, integer meaning "entire", and -folium meaning "foliage or leaves". 

Butterfly/moth host plant: Silphium borer moth (Tabenna silphiella)

all photos by Nathanael Pilla

photo by Nathanael Pilla

Landscape: A unique plant that needs some space in your landscape.  It offers dinosaur-sized leaves and gorgeous flowers.  One downfall is that it can flop over in heavy winds.  Birds enjoy the seeds.

Species Present and Native