Prairie Dock - Silphium terebinthinaceum

Silphium terebinthinaceum, also known as Prairie Dock, is a perennial wildflower native to southern Michigan. Prairie Dock reaches 9 (yes 9!) feet tall and flowers from July to September with a vase of yellow blossoms beloved by pollinators on long stalks.  
 
Although the flower stalks reach for the heavens, most of the plant consists of a cluster of giant showy leaves near the ground (see the third picture).  This allows Prairie Dock to be a dramatic centerpiece without obstructing the view. The giant leaves have a tropical feel and are my favorite part!
 
According to the U.S. Forest Service Fact Sheet on this plant, the leaves tend to orient themselves with the edges north and south, and the face of the leaves facing east/west, to maximize daylight hours on the leaf surface while reducing hot sun exposure and transpiration at midday. The leaves are said to feel cool to the touch during the heat of the day. 
 
Prairie Dock needs full sun (6 or more hours of direct sun at midsummer) to grow its straightest, but will tolerate partial shade (3-6 hours of sun; may lean toward the light).  It is suited for medium to dry soil and will grow in clay, loam or sandy soil.  Once established, its deep taproot makes it drought tolerant.  
 
Although it will take a few years, this plant will get wide as well as tall. Give it room to fill out by spacing at least two feet from buildings, tree drip lines, or favorite plants you do not want to crowd. While waiting for it to fill in, control weeds by filling in the empty space with a matrix plant such as Prairie Sage or Black-eyed Susan.
 
Prairie Dock is a favorite of bees and is visited by hummingbirds. In fall, its large seeds are enthusiastically sought after by birds. It has some of the largest seeds of any Michigan native plant. Nature's bird feeder! It is nicely deer and rabbit resistant.  Prairie Dock makes a lovely garden showpiece or backdrop with a lot of drama and texture, and also naturalizes well into meadows or along paths and roads.  Pairs well with Prairie Blazingstar, Big Bluestem and Indian Grass.