Common Name: Rush Milkweed

General Information

Asclepias subulata is an erect shrub with both unbranched and branched stems; it can grow up to 2 metres tall. Adapted to very dry environments, the stems are leafless except when very young - the stems are green, however, and carry out the process of photosynthesis[, ].
The plant can be harvested from the wild for local medicinal use and is a potential source of latex for making rubber.

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

South-western N. America - California, Nevada, Arizona, northern Mexico

Habitat

Desert washes and sandy places; at elevations below 600 metres in California[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	2.00 m
Pollinators	Bees, Insects, Lepidoptera
Cultivation Status	Wild

Cultivation Details

Asclepias subulata is a plant of dry Mediterranean climates with hot summers and cool or even cold winters and most precipitation falling in the cooler months. Outside of this type of climate, the plant will require a well-drained soil and hot summers, with some protection in cold winters, if it is to thive. This protection can often be applied as a mulch, though it would need to be removed before new growth begins in the spring otherwise slug damage is very likely to occur[].
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[].
Plants can live for more than 100 years[].
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

None known

Medicinal

The plant is emetic, ophthalmic, purgative and stomachic[, ]. The reports do not specify which part of the plant is used.

Other Uses

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

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.