Sold Out for 2013. More than just a little splash of color for your late summer/fall perennial or woodland garden, Aconitum napellus, or Monkshood, stands anywhere from three to six feet tall with beautiful dark green, deeply lobed leaves and violet/blue hooded flowers. Monkshood is perfect for the back of the border and also for naturalizing at the edge of a woodland garden. This native perennial wildflower does best with a little shade and cool, fertile soil. Most varieties of Aconitum are extremely poisonous. Zones 4-8. Quarts.