We have already discussed the Butterfly weed (Asclepias tuberosa) in a previous post, but two other species are often recommended for a butterfly garden so we will look at them next.
Swamp Milkweed (Asclepias incarnata) is also known as Rose milkweed, Pleurisy root or White Indian hemp. This species has fragrant deep pink, light purple or white flowers clustered at the tops of long branching stems in the summer. Numerous narrow, lanceolate leaves progress in pairs up the stems.
This native, perennial wildflower grows to a height of between one and six feet tall, depending in part upon the environment in which it is planted. In the fall, the blooms are replaced by distinctive 5″ tear shaped seed pods that are green before ripening into brown. When the seeds are released they drift on comas (downy parachutes) in the wind to propagate. They increase in size by sending our rhizomes but are not considered invasive. Good information on propagation by seed can be found at the USDA NRCS website.
This is a moisture loving plant that does well when planted in moist soil or near streams. It likes moist habitats such as wet meadows, stream banks, damp woods, swamps and marshes. It will also grow in drier areas like prairies, fields and roadsides. It does best when planted where it will get full sun or partial shade. It can tolerate heavy clay soil and is deer resistant.
The swamp milkweed is an important host plant for the monarch butterfly (Danaus plexippus) larvae and the queen butterfly larvae (Danaus glippus). It also draws other butterflies and hummingbirds. Bloom time is July through August and they are hardy in zones 3-9. It is deer resistant but may draw aphids.
Fun facts: The Iroquois and Chippewa used an infusion from the roots of the swamp milkweed externally to strengthen the body and to heal babies’ navels, The common name of Pleurisy Root stems from its being used to treat lung problems. The soft comas that are attached to the seeds when they are released from the milkweed pods were used as stuffing for pillows and lifejackets during WW II. They are 6 times more buoyant than cork and 5 times warmer than wool (USDA NRCS Fact Sheet).
Ripe Milkweed Pod with Comas
Photo of the Swamp Milkweed Bloom by Jennifer Anderson. United States, IA, Scott Co., Davenport, Nahant Marsh. 2002.
The common milkweed (Asclepias syriaca) is also a favored host plant for the Monarch butterfly (Danaus plexippus). Other names for this plant are virginia-silk and silky swallowwort. It is a tall, unbranched plant ranging in height from 2-6″. The flower clusters droop slightly and vary in color from faded light pink to reddish purple. The flowers are quite fragrant, similar to pansies. Bloom time is June into August. It is hardy in zones 3-9. The leaves are 4-10″ in length, broad and oblong and arranged opposite to each other up the common stem. The seedpods are prickly which differentiates it from other milkweeds.
When either the leaves or the stems are broken or torn, a white milky sap is released. The sap contains cardiac glycosides which are a naturally occurring drug which has both beneficial and toxic effects on the human heart. It is these glycosides that provide a chemical defense for the butterflies and caterpillars that use it for food.
The Asclepia syriaca prefers full sun and rich, loamy soil but can tolerate partial sun and sandy or clay soils. They are found along the banks of ponds, streams and other waterways, thickets, fields, fence rows and roadsides. It will colonize in disturbed areas, natural and developed.
The flowers are popular with multiple insects, including long-tongued bees, wasps, flies, skippers and butterflies, for their nectar. The larvae of the Monarch Butterfly, the Milkweed Tiger Moth (Enchaetes egle), the Unexpected Cycina (Cycina inopinatus), and the Delicate Cycina (Cycina tenera) feed on this plant.
Propagation is both by seed and rhizome cuttings. Because it increases its size through underground rhizomes, it can be invasive. This needs to be considered when deciding where to plant it.
Fun Facts: Indian tribes used the common milkweed to treat various physical ailments including:
- drinking an infusion of the root and virgin’s bower (Clematis) for backaches
- using the sap to treat warts, ringworm and beestings
- infusions were used for mastitis, venereal diseases, and colds
- an infusion from the leaves was used for stomach ailments
- in various forms it was used for a laxative, as a contraceptive, to prevent postpartum hemorrhage, and to produce postpartum milk flow
Common Milkweed Photo by Jennifer Anderson. United States, IA, Scott Co.
Delicate Cycnia Milkweed Tiger Moth
|Illinois WildflowersUSDA NRCS Plant Guide Swamp MilkweedNorthern VA EcologyUSDA NRCS Plant Guide for Common MilkweedUSDA NRCS Plant Guide for Swamp MilkweedNorth American Butterfly Association Swamp Milkweed and Common Milkweed|