Silphium trifoliatum (Whorled Rosin Weed)
Silphium trifoliatum (Whorled Rosin Weed)
150 (300)cm, Whorled Rosin Weed is a very showy, tall herbaceous species with lance-shaped to ovate leaves arranged in distinct whorls of three to five and sunflower-like bright yellow flowers. Native of rich soils in open woods. Easily grown in a rich, well drained soil in a partially shaded to sunny spot. VII-IX.More Details »