Purple Silkweed, Hall's milkweed
Asclepias hallii
Family: Asclepiadaceae
What it is like
Asclepias hallii is a PERENNIAL growing to 1 m (3ft 3in) by 0.6 m (2ft). See above for USDA hardiness. It is hardy to UK zone 3. It is in flower from June to August, and the seeds ripen in September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, insects, Lepidoptera (Moths & Butterflies). The plant is self-fertile. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil.
Height (m): 1
Where it is found
Sandy soils of prairies and roadsides.
Western N. America - Wyoming to Colorado, south to Nevada and S. Arizona.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 3
The following uses have been recorded for A. speciosa, it is fairly safe to assume they can also be applied to this closely related species. Flower buds - raw or cooked. Tasting somewhat like peas. Young shoots and leaves - cooked. An asparagus substitute. They should not be eaten raw. Tips of older shoots are cooked like spinach. Young seed pods, 3 - 4 cm long, cooked. Very appetizing. Flower clusters can be boiled down to make a sugary syrup or they can be eaten raw. Seed - raw. A chewing gum can be made from the latex contained in the stem and leaves. Root. No further details.
Oil: Oil
Seed: includes nuts, cereals, peas and beans.
Seedpod: things such as Okra, French and Runner beans.
Gum: can be chewed as a chewing gum or can often be used as a sweetener or thickening agent in foods.
Sweetener: includes sugar substitutes.
Medicine
Rating: 1
The following uses have been recorded for A. speciosa, it is fairly safe to assume they can also be applied to this closely related species. The latex is used as a cure for warts. A tea made from the whole plant has been used as a contraceptive after childbirth.
Contraceptive: Prevents fertilization occurring in females.
Warts: Used in the treatment of warts, corns etc.
Other
Rating:
The following uses have been recorded for A. speciosa, it is fairly safe to assume they can also be applied to this closely related species. A good quality tough fibre is obtained from the bark. It is used in twine, coarse cloth, paper etc. The fibre is 10 - 45mm long. It is easily harvested in late autumn, after the plants have died down, by simply pulling it off the dead stems. When making paper, the stems can be retted by leaving them in the ground until they are dry in the winter or they can be harvested in late summer, the leaves removed and the stems steamed to remove the fibre. The stems are then cooked for two hours with lye and pounded with mallets. The paper colour varies from white to creamy green depending on how the paper is made. If the stems are used in the summer the latex will often find its way onto the fibres and is hard to remove. 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. 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 the stems. The yield is up to 3%. Pods contain an oil and a wax which are of potential importance. A green dye is obtained from the flowers and leaves combined.
Dye: Plants that provide dyes.
Fibre: Used for making cloth, rope, paper etc.
Gum: Gums have a wide range of uses, especially as stabilizers, emulsifiers, thickening agents, adhesives etc.
Latex: A source of rubber.
Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.
Paper: Related to the entry for Fibre, these plants have been specifically mentioned for paper making.
Pollution: Plants used to combat pollution.
Stuffing: Used in making soft toys, mattresses, pillows etc.
How it is grown
Prefers a well-drained light rich or peaty soil and a sunny position. This species is closely related to A. purpurascens. 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.
Propagating it: 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.
Best place to grow: Cultivated Beds;
Habit: Perennial
Hardiness: 3-7
Growth:
Soil: Light (sandy), medium
Shade: Semi-shade, no shade
Moisture: Dry, moist
Things to keep in mind
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 usually avoided by grazing animals.