This article by Hubert Ling (NPSNJ horticulture) was published in Gardener's News without the photos. He is a regular contributing writer to Gardener's News. Photos by H & M Ling.

Swamp Milkweed: Asclepias incarnata

Swamp Milkweed
Would you like to save the world or at least a part of it?

Would you like to save the world or at least a part of it? Well then plant our native swamp milkweed! Much of the world's wildlife is in steep decline due to loss of habitat; butterflies have been particularly hard hit with a 96% drop in monarch butterfly population during the last 17 years. Milkweeds are a favorite food for caterpillars and are also a favorite nectar food for the adult butterflies, moths, bees, and hummingbirds.

The name milkweed comes from the fact that the plant if injured releases large amounts of milky sap which contains 1-2% latex and toxic cardiac glycosides. Thomas Edison and later scientists, in both Germany and the US tried to use this latex as a rubber substitute but these attempts were not successful on a commercial scale.

Swamp milkweed, Asclepias incarnata, grows 3-5' tall and is a native perennial although as with other "soft perennials" the plant must be replaced with seedlings about every 6 years since older plants have a tendency to die off. In NJ swamp milkweed produces showy clusters of soft pink, fragrant flowers in July followed in fall by narrow pods packed with silky "parachutes" (comas) attached to a 1/4" flat brown seed.

The silky material from various species of milkweed, although possessing a beautiful silky sheen, has seen very limited use as thread since the fibers are short and brittle and are thus difficult to spin by traditional methods. This material, however, has been widely used as a shimmering backdrop for framed arts and crafts projects. It was initially used primarily to provide a luxurious background for pressed butterfly displays, but in our more ecologically sensitive era, it now makes a great background for pressed flowers and ferns. During World War II millions of pounds of milkweed fluff were collected by patriotic children for pillow stuffing and in lifejackets. This silky material is currently being experimented on as a humane and superior replacement for down insulating material for jackets, sleeping bags etc.

Although the internet will explain how to get a butterfly kiss from a loved one right here and now in this article I will explain the mysteries of how to get a real butterfly kiss! First grow several swamp milkweed plants. Next position yourself near some newly matured flowers, use care to avoid pollen or bees if allergic. When a butterfly lands slowly position your nose or cheek very near to the butterfly; the butterfly will naturally flex its wings upon landing and give you the light brushings of a genuine wild butterfly kiss!

Swamp milkweeds are easy to grow. They are generally started from seed: simply sow the seeds in a good garden soil as soon as they are ripe in the fall and cover them with about ΒΌ" of soil. A light mulch can be added but this must be removed gradually starting in April so as not to smother the young seedlings. Although as the name implies, swamp milkweed does very well in heavy, damp soil, it will also grow well in lighter, slightly acid to neutral soil, with moderate watering. They are found growing naturally in damp, full sun to partially shady areas, in the US and Canada from Quebec south to Florida and west to Nevada and are somewhat deer resistant.

Swamp milkweed is toxic if taken in large amounts but if used in smaller doses the Native Americans found that this semi-toxic mash was a good emetic and worming agent. The monarch butterfly accumulates these toxins within its body without harm; the end result is a very bad tasting butterfly and birds soon learn to avoid monarchs. A few people develop dermatitis from contact with milkweeds. The tough fibers of swamp milkweed stems can be used by humans to make twine, rope, and fabrics and birds such as orioles find them useful for nest construction.

Swamp milkweed plants are found at many garden shops and 2 cultivars as well as the native species are available: 'Ice Ballet' is a white selection and 'Cinderella' is the normal pink but with an extended blooming season.  

See more photos in our summer photo gallery: summer photo gallery, swamp milkweed,