FIELD NOTES: The Milkweeds
Butterfly weed. photo by Michele Bland Pollock
~by Jim Eagleman
E
ach early summer milkweeds make a grand display near my home, filling abandoned fields and roadsides with dense clusters of yet-to-open, pinkish-purple flowers. Gazing out over rolling terrain, I see many individual patches containing dozens of soon-to-be mature milkweed plants. Some newly purchased native milkweed rootstocks for our natural area are slow to mature, but soon more young starts will appear. This growth pattern occurs because the perennial milkweed propagates by means of an underground root called a rhizome. Extending in all directions, the rhizome sends up a multitude of flowering stalks. Each colony of milkweeds in a field or garden may actually be a single clone of plants growing from a common root system. Common milkweed, one of many genera, has a range from southwestern US deserts to the Rockies and across the east. Found in fields, waste areas, and roadsides, they don’t seem to have a preference where they grow. The milkweed genus, Asclipias
54 Our Brown County July/August 2021
comprises nearly 100 species and most are native to North and South America. The name Asclepias comes from Asklepios, the Greek god of medicine. He is usually depicted carrying a staff intertwined with a snake, the modern day symbol of medicine. So it comes as no surprise milkweeds have been used for a wide variety of ailments, experimentally, including asthma, dysentery, heart disease, stomachaches, snakebites, ringworm, warts, tapeworms, and even syphilis. Its popularity as a medicine may be related to the supply of a bitter, milky latex produced in a special system of tubes that branch throughout the plant. The latex contains a substance identified as a cardiac glycoside. In small doses it can cause nausea and vomiting. In larger doses, as a poison to vertebrates. For the plant, the latex acts as a defense, visible when a leaf stem is pinched and the white liquid oozes out. When exposed to air it quickly dries and becomes sticky, gumming up the mandibles (mouthparts) of insects. Very few insects can tolerate the latex from milkweeds, but several are
