Helping Aubie this week is Dr. Mike Patterson, Extension Weed Scientist with the Department of Agronomy and Soils, in AU’s College of Agriculture.

Dear Graham, Tre, Marlee and Aysia,

            Milkweed is the common name for a group of plants in the genus Asclepias (A-sleep-e-us).  They belong to the family Asclepiadaceae composed of perennial plants that are described as erect or twining, usually having milky sap and having spindle-shaped or fibrous roots.  The leaves are usually simple with smooth margins and lance-shaped to widely oval.  They are usually arranged in opposite fashion on the stem and the flower cluster is shaped like an upside down umbrella.    Milkweed flowers are showy and range in color from white to yellow to red.  Mature milkweed plants range in height from 2 to 8 feet, depending on the species.  There are approximately 20 species indigenous to the Eastern United States and many of these can be found in Alabama.
    
All species of milkweed tested have been found to be toxic to livestock such as cows (and probably to humans).   Milkweed sap is considered an irritant to the skin and eye.  However, butterfly caterpillars feed on these plants and the emerging butterflies are then protected from several species of birds due to the level of milkweed toxin in these insects.  The Monarch butterfly is known to lay its eggs on Asclepias tuberosa (commonly called butterfly weed or butterfly milkweed).  Butterfly weed grows to a height of about 4 feet from a woody rootstock.  The stem is erect and all parts of the plant are hairy. 

Leaves are attached directly to the stalk.  The plant flowers from May to August and produces seed in late-summer to fall.  Flower color is generally yellow to orange-red.  Butterfly weed is one of the few Asclepias species that does not have milky sap.  A synonym for butterfly weed is “pleurisy-root,” as the root of this plant was at one time used to make a home remedy for pleurisy.

Thanks for your question,
Aubie and Dr. Patterson