Get as many goldenrod flowers as you can and pack them into a cleaned jar with a screw-top cap. Add (slowly) extra virgin olive oil through the flowers until there is a small layer of olive oil covering the flowers. Screw the cap on and invert the jar back and forth about 3-5 times-- you are trying to make sure there are no air bubbles in the middle of the flowers. Seal it tightly and place in a cool, dark place for about 6 weeks. Strain through a cheesecloth and store the oil in a brown/blue bottle in a cool place.