USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner’s Sons, New York. Vol. 3: 30. Common milkweed is a perennial, herbaceous plant that grows to heights of 2 to 6 feet on solitary