Silphium terebinthinaceum - Prairie Dock
Prairie Dock (Silphium terebinthinaceum) is a bold, and long-lived perennial. It is easily distinguishable by its cluster of very large, spade-shaped basal leaves and one or more naked flowering stalks that rise from the base of the plant. The stalks are green or reddish-purple, and at the top divide gracefully into a panicle of yellow flowerheads and round green buds. The species name "terebinthinaceum" means "like turpentine," referring to the odor of its stem resin.
Soil Moisture: Moderate, Wet
Sun Exposure: Full Sun
Height: 4' - 9'
Spread: 2' - 4'
Hardiness Zone: 4 - 8
Bloom Color: Yellow
Bloom Time: July, August, September
Attracts: Birds, Pollinators
Silphium is a genus of flowering plants that are native to North America, and is commonly referred to as rosinweeds. They are very tall perennials that can grow taller than 8 feet, and have yellow flowers that can resemble sunflowers. With rosinweeds, the flower's outer florets are fertile and the inner florets are sterile, but in sunflowers it is the opposite. Silphium is an ancient Greek word for a North African plant whose identity has been lost and was claimed to be extinct in Roman times, but its gum or juice was prized as a medicine and condiment.
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