Rush Milkweed
Asclepias subulata
Family: Asclepiadaceae
What it is like
Asclepias subulata is a PERENNIAL growing to 2 m (6ft 7in). See above for USDA hardiness. It is hardy to UK zone 6. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, insects, Lepidoptera (Moths & Butterflies). Suitable for: light (sandy) soils, prefers well-drained soil and can grow in nutritionally poor 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): 2
Where it is found
Desert washes and sandy places below 600 metres in California.
South-western N. America.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 0
Medicine
Rating: 1
The plant is emetic, ophthalmic, purgative and stomachic. The reports do not specify which part of the plant is used.
Emetic: Induces vomiting.
Ophthalmic: Treats eye complaints.
Purgative: A drastic laxative causing a cleansing or watery evacuation of the bowels, usually with a griping pain.
Stomachic: Aids and improves the action of the stomach.
Other
Rating: 0
Rubber can be made from latex contained in the leaves and the stems. The dogbane-milkweed family Asclepias, Apocynum, Calotropis, and Trachomitum spp) has been used for fiber industrial crops for millennia with a number in cultivation as regional crops. All of these crops are dual-purpose fibres, offering bast fibres from the stem and seed finer or ‘floss’ in the fruit pods. Many have also been identified as potential hydrocarbon crops due to high latex content. Could be integrated into various agroforestry systems rather than as monocultures.
Latex: A source of rubber.
Experimental Crop: Plant breeders are testing these plants to see if they could be domesticated for cultivation, but they are still in an experimental phase. Examples include milkweed and leafy spurge.
Industrial Crop: Hydrocarbon: Materials, chemicals and energy include bioplastics, rubber, biomass products gasoline, jet fuel, diesel, butane, propane, biogas. Plants are usually resprouting plants and saps.
Management: Hay: Cut to the ground and harvested annually. Non-destructive management systems maintaining the soil organic carbon.
Experimental Crop: Plant breeders are testing these plants to see if they could be domesticated for cultivation, but they are still in an experimental phase. Examples include milkweed and leafy spurge.
Industrial Crop: Hydrocarbon: Materials, chemicals and energy include bioplastics, rubber, biomass products gasoline, jet fuel, diesel, butane, propane, biogas. Plants are usually resprouting plants and saps.
Management: Hay: Cut to the ground and harvested annually. Non-destructive management systems maintaining the soil organic carbon.
Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.
How it is grown
Prefers a well-drained light rich or peaty soil in a sunny position. Succeeds in poor soils. 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. A xerophytic plant, it looks like a species of Ephedra. 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: 5-9
Growth:
Soil: Light (sandy)
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. One report says that the plant is considered poisonous by some native North American Indian tribes.