Common Name: Red Silkweed

General Information

Asclepias rubra is an erect, herbaceous perennial plant producing a cluster of slender, unbranched stems 40 -150cm tall from a usually tuberous rootstock[, ].
Like most, if not all Asclepias species, the plants are likely to have been utilized for foods and other materials by the native North American tribes. See Asclepias syriaca for some idea of these potential uses[].

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

Eastern N. America - New York to Florida, Missouri, Louisiana and Texas.

Habitat

Moist soils[]. Bogs, marshes, wet meadows, and low pine barrens[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.20 m
Pollinators	Bees, Insects, Lepidoptera
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Prefers a well-drained light rich or peaty soil and a sunny position[, , ].
A very ornamental plant[], it is closely related to Asclepiad lanceolata[].
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 resent root disturbance and are best planted into their final positions whilst small[].
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[, ].

Edible Uses

Flower buds - cooked as potherbs or added to soups[].

Young shoots and leaves - cooked as potherbs or added to soups[].
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, 3 - 4 cm long, cooked[].

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

A chewing gum can be made from the latex contained in the stem and leaves, but it is possibly toxic[].

Medicinal

The latex is used as a cure for warts[].

Other Uses

The following reports refer to other members of this genus and are possibly also appropriate for this species[].

A good quality fibre is obtained from the bark, used in making twine, cloth, paper etc[, , ]. It is of poor quality in wet seasons[]. It is easily harvested in late autumn after the plant has died down by simply pulling the fibres off the dried stems[].

The seed floss is used to stuff pillows etc or is mixed with other fibres to make cloth[, , , ]. It is a Kapok substitute, used in Life Jackets or as a stuffing material[]. Very water repellent, it can yield up to 550 kilos per hectare[]. The floss has also been used to mop up oil spills at sea. Candlewicks can be made from the seed floss[, ].

Rubber can be made from latex contained in the leaves and the stems[, , , ]. It is found mainly in the leaves and is destroyed by frost[]. Yields are higher on dry soils[].

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

The seed contains up to 20% of an edible semi-drying oil[, ]. It is also used in making liquid soap[].

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..
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.