Plant of the Week: Common Millkweed (Asclepias syriaca)

This species has received a bad rap by farmers because it is considered weedy and has the tendency to spread profusely into agricultural fields.  When you look at it more closely, it is weedy under the right conditions, where the soils are good and loamy or sandy loam.  It, like most other milkweeds, does not like clay soils and can be difficult to establish in a native plant butterfly garden.  It will send out underground rhizomes and form a nice patch, but it generally does not spread like wildfire throughout neighborhoods.   This species can reach heights of 2 -6' tall and in late June produces beautiful pink flowers shown in the photo above in a 2- 4" cluster shown below that is very fragrant with a smell like pansies or violets .  The flower clusters are showy and highly attractive to insects, particularly butterflies. The plant is toxic to mammals and there are cardiac glycosides in the milky sap which means that many species of insects, including many that are very showy, because they are toxic if eaten. This is a largely unbranched plant and the stem has short hairs.  The large opposite leaves are hairless above and downy on the underside and each one has a prominent central vein. The seed pods are also unique with an elongated pear shape with short prickles and hairs.  The seeds have long hairs and are dispersed by the wind.  This is one of the milkweeds that is the host plant for monrach butterflies.  But other insects are also attracted to it and include things like short-tongue bees, milkweed plant bugs and moths, predatory wasps and a whole host of butterflies, particularly hairstreaks.  It is one of the very best butterfly attracting plants available.  For use in the garden, it is best placed in full sun where it has room to spread but can be controlled by cutting the rhizomes off under the soil.  Once established it requires no care whatsoever.  So if you are looking for something fragrant that butterflies absolutely love, this is the plant for you.