Common Name: Swamp Milkweed

General Information

Asclepias incarnata is an erect, herbaeous perennial plant forming a cluster of 2 - 5 unbranched to densely branched stems; it generally grows 90 - 120cm tall, exceptionally to 150cm[, , ].
The plant was much used by native N. Americans as a food, medicine and source of materials - it warrants present day attention as a potential cutivated crop, especially for fibre[]. The plant is often grown as an ornamental, some named forms have been developed.

Known Hazards

Although no specific reports have been seen for this species, many, if not all, members of this genus contain toxic resinoids, alkaloids and cardiac glycosides. They are only toxic if eaten in large quantities, causing vomiting, stupor, weakness and spasma[, ].
The plants are usually avoided by grazing animals[].

Botanical References

, ,

Range

Central and eastern N. America - Manitoba to Nova Scotia, south through Montana to Arizona, Texas and Florida

Habitat

Swamps, wet thickets and shores[]. The subspecies pulchra is frequently found in somewhat brackish tidal marshes[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.00 m
Pollinators	Bees, Insects, Lepidoptera
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Plants are hardy to at least -25°c[].
Although native to swamps and wet meadows, the plant is surprisingly tolerant of average, well-drained soils in cultivation[]. It prefers a well-drained light rich or peaty soil[, ]. Requires a moist soil and a sunny position, doing well by water[, ]. Succeeds on dry soils and on all soil types[]. The subspecies pulchra is tolerant of more or less brackish water[].
A very ornamental plant[], the flowers are very attractive to butterflies[].
The flower of many members of this genus can trap insects between its anther cells - the struggles of the insect in escaping (especially bees and wasps) pulls with it the pollinium (sacs of pollen) which are then transported to the next flower and deposited there, ensuring pollination of the flower[, ].
The foliage is slow to emerge in spring[].
Many members of this genus seem to be particularly prone to damage by slugs. The young growth in spring is especially vulnerable, but older growth is also attacked and even well-established plants have been destroyed in wet years[].
Plants have deep taproots; they resent root disturbance and are best planted into their final positions whilst small[, ].

Edible Uses

Unopened flower buds - cooked[, , ]. Tasting somewhat like peas[]. They can also be dried and stored for later use[].

Young shoots - cooked. An asparagus substitute[, ].
Tips of older shoots are cooked like spinach[].
One recipe suggests you parboil the leaves or young shoots for three minutes, then discard the bitter water and replace with clean boiling water. (Cold water tends to fix the bitterness.) You can repeat this process p to three times to fully leach any bitterness (and many of the nutrients[]), then cook the leaves for 15 minutes before seasoning them. A pinch of soda can be added during cooking to break down the fibe and improve flavour[].

Young seed pods, harvested when 3 - 4 cm long - cooked. A pea-like flavour, they are very appetizing[].

The flower clusters can be boiled down to make a sugary syrup[].

Medicinal

A tea made from the roots is anthelmintic, carminative, diuretic, emetic, strongly laxative and stomachic[, , , ]. The tea is said to remove tapeworms from the body in one hour[]. It has also been used in the treatment of asthma, rheumatism, syphilis, worms and as a heart tonic[, , ].
An infusion of the roots is used as a strengthening bath for children and adults[].

Other Uses

A good quality fibre is obtained from the bark[, , , , , ]. It is used in twine, cloth etc[]. The fibre is
finer than hemp as usually prepared, soft and glossy, possessing greater strength than the majoi-ity of bast fibers of wild growth in the United States. It is useful for all purposes to which hemp maybe applied[].
The fibre is easily harvested in late autumn, after the plants have died down, by simply pulling it off the dead stems[].

The seed floss is used to stuff pillows etc or is mixed with other fibres to make cloth[, ]. It is a Kapok substitute, it is used in Life Jackets or as a stuffing material[, ]. It is very water repellent. The floss has also been used to mop up oil spills at sea.

Rubber can be made from latex contained in the leaves and stems[].

Pods contain an oil and a wax which are of potential importance[].

Propagation

Seed - best sown in a greenhouse as soon as it is ripe in the autumn or in late winter[, ]. We have also had good results from sowing the seed in the greenhouse in early spring[], though stored seed might need 2 - 3 weeks cold stratification[]. Germination usually takes place in 1 - 3 months at 18°c[]. As soon as the seedlings are large enough to handle, prick them out into individual pots and grow them on in the greenhouse for their first winter. Plant out when they are in active growth in late spring or early summer and give them some protection from slugs until they are growing away strongly.
Division in spring. With great care since the plant resents root disturbance. Pot the divisions up and place them in a lightly shaded position in the greenhouse until they are growing away strongly, then plant them out in the summer, giving them some protection from slugs until they are established..This species has a deep taproot and resents root disturbance[]. It is unlikely to repond well to attempts to divide it[].
Basal cuttings in late spring. Use shoots about 10cm long with as much of their white underground stem as possible. Pot them up individually and place them in a lightly shaded position in a greenhouse until they are rooting and growing actively. If the plants grow sufficiently, they can be put into their permanent positions in the summer, otherwise keep them in the greenhouse until the following spring and when they are in active growth plant them out into their permanent positions. Give them some protection from slugs until they are established.