Asclepias tuberosa or the common butterfly weed is one of many native herbaceous perennials that burst into full bloom in June.
The plants have very thick roots and form a mounded clump of green foliage in May, then in June the beautiful flowers begin to open, a bright orange, sometimes yellow or red in color. They grow in full sun and love our Eastern Shore sandy soils, and once established they are very tolerant of drought.
As with a lot of native flowers, the Asclepias tuberosa has many common names including Butterfly milkweed, orange milkwed, chigger flower and pleurisy root.
All of the common names are great at describing the plant, as butterflies flock to the bright orange flowers of the butterfly weed plants.
The name “milkweed” comes from the milky white sap that seeps out of plants when the stems or leaves are broken off. Some find the milkweed sap irritating to their skin.
The name “chigger flower” is a way to alert gardeners not to dig up the wild plants without walking into a possible pesky insect.
Pleurisy root highlights the medicinal uses of the plants that in the past were very helpful in relieving the difficulty of breathing. Butterfly weed flowers cluster together to create a bright bouquet on the top of the plants, easy for many pollinators to find.
The nectar in the bright orange flowers attract many different types of butterflies, bringing color and motion into the sunny garden, but the Monarch butterfly actually needs the Butterfly weed to survive! The bright orange and black with white spotted Monarch butterfly has been called the “king of butterflies” because it is so beautiful and colorful.
The female Monarch Butterfly will lay her eggs only on the milkweed plants, one egg to each plant, and within four days the eggs hatch out the black, yellow and white stripped caterpillars that feed on the leaves of the milkweeds.
The host plant of milkweed has toxins that the Monarch caterpillars can eat without any problems, but any of their predators of the caterpillar will find it either unpleasant or distasteful to eat. The caterpillar eats its way through five stages of increasingly larger caterpillars on the Butterfly weed plant.
Every stage occurs when the caterpillar gets too large for its skin.
It sheds the skin and then eats the old skin before enjoying more milkweed leaves.
Once it has reached the largest stage as a caterpillar, it usually departs from the butterfly weed plants to find a safe place to change from a caterpillar to a butterfly. The caterpillar sheds its skin for the last time to expose the bright green inch long chrysalis with gold colored spots.
The chrysalis hardens up within hours and the changes inside the chrysalis are amazing. This stage of the Monarch is called a pupa and all it can do is hang around and continue to change inside. After a week or two, depending on the summer temperatures, the chrysalis is ready to reveal its hidden treasure.
About a day before the butterfly is ready to emerge, the color of the chrysalis darkens and the ‘skin’ becomes transparent, allowing a view of the butterfly wings. The next morning the Monarch butterfly emerges and sits for several hours to allow the wings to fill out and dry.
Once it is ready, the Monarch butterfly will fly to the garden to drink the nectar of the butterfly weed flowers and other flowers it can find. Monarch butterflies are listed as endangered due to the drop in numbers in the past few years.
Planting Asclepias tuberosa or butterfly weed flowers in the Eastern Shore gardens will help insure that the Monarch butterflies will have a better chance of continuing to survive and thrive.
(Editor’s Note: Ginny Rosenkranz is a commercial horticulture specialist with the University of Maryland Extension.)
