Asclepias obtusifolia latifolia Torr.
Otanema latifolia Raf.
Common Name: Broadleaf Milkweed
Asclepias latifolia is an erect, herbaceous perennial plant producing a cluster of stout, unbranched or lightly-branched stems 20 - 60cm tall[
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[
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[
Central and south-western N. America - California to Nebraska, south to New Mexico and Texas
Dry plains and prairies[
]. Mixed prairies, badlands, and high plains, spreading to roadsides and railways[
|Pollinators||Bees, Insects, Lepidoptera
Prefers a well-drained light rich or peaty soil in a sunny position[
]. Succeeds in poor, dry soils. Established plants are drought tolerant.
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[
The leaves and stems can be dried then ground into a powder and inhaled as a snuff in the treatment of catarrh[
Rubber can be made from latex contained in the leaves and the stems[
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.