Asclepias rubra

Red silkweed

Apocynaceae Edible: Flowers, Gum, Leaves, Seeds pod Potential hazards — see below 571 iNaturalist observations

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Summary

A tall perennial milkweed reaching 1.2m. Hardy to UK zone 5. Flowers June to August with seeds ripening in September. Self-fertile hermaphrodite flowers pollinated by bees, insects, and lepidoptera. Prefers sandy to loamy, well-drained soils with mildly acid to alkaline pH. Tolerates semi-shade or full sun in dry or moist conditions.

Description

Edible Uses

Edible Parts: Flowers Leaves Seedpod Shoots Edible Uses: Gum Sweetener Flower buds - cooked as potherbs or added to soups. Young shoots and leaves - cooked as potherbs or added to soups. 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.

Traditional Uses

The flowers are boiled down to make a sugary syrup.

This uses section is brief — help expand it

Medicinal Uses

Warts The latex is used as a cure for warts.

Known Hazards

Milkweed latex contains about two percent latex, and during World War II both Nazi Germany and the US attempted to use it as a source of natural rubber, although no record of large-scale success has been found. Many milkweed species also contain cardiac glycoside poisons that inhibit animal cells from maintaining a proper K+, Ca2+ concentration gradient. As a result, many peoples of South America and Africa used arrows poisoned with these glycosides to fight and hunt more effectively. Some milkweeds are toxic enough to cause death when animals consume large quantities of the plant. Some milkweeds also cause mild dermatitis in some who come in contact with them. Nonetheless, some species can be made edible if properly processed.

Distribution

It is a temperate plant.

Where It Grows

North America, USA,

Cultivation

Prefers a well-drained light rich or peaty soil and a sunny position. A very ornamental plant, it is closely related to A. 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 ensure the pollination of the plant.

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.

Other Uses

Fibre Gum Latex Stuffing 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. Special Uses

Notes

There are 100 Asclepias species.

Synonyms

Asclepias acuminata PurshAsclepias cordata WalterAsclepias lancifolia Steud.Asclepias laurifolia Michx.Asclepias periplocifolia Nutt.Asclepias polystachya WalterAsclepias rubra var. laurifolia (Michx.) R.M. Harper