Asclepias syriaca L.
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Gaertner (1979) speaks of milkweed as "the greatest underachiever among plants.
Its potential appears great, yet until now it has never been continuously
processed for commerical purposes." The latex has been suggested as a suitable
replacement for chicle in chewing gum rather than for rubber in tires. It was
once cultivated in Europe for bee fodder and fiber. Two types of fiber are
obtainable, the long, quite strong but brittle bast fiber and the seed hairs.
Pulp from the fiber yields a good paper. During World War II, the seed hairs,
being rather springy, light and waterproof, were used to replace kapok in life
jackets. Flowers are reported to be a source of sugar and have been used, with
sugar and lemon, to make wine. Gaertner says, "Milkweed makes an attractive
pot herb in many forms: first as a young shoot, then as unopened buds, and
finally as pods, while these are still young, and the seeds are not yet
differentiated." I have tried all these, discarding my first "potlikker", and
found them quite palatable. Some Indian groups dried the flower buds in summer
for use in winter soups (Erichsen-Brown, 1979). I have not tried the "boiled
roots" which Kloss (1939) states "taste similar to asparagus." I suspect this
is a typo for shoots.
According to Hartwell (19671971), the leaves and/or latex are used in folk
remedies for cancer, tumors, and warts. Reported to be alterative, anodyne,
cathartic, cicatrisant, diaphoretic, diuretic, emetic, emmenagogue,
expectorant, laxative, and nervine. Milkweed is a folk remedy for asthma,
bronchitis, cancer, catarrh, cough, dropsy, dysentery, dyspepsia, fever,
gallstones, gonorrhea, moles, pleurisy, pneumonia, rheumatism, ringworm,
scrofula, sores, tumors, ulcers, warts, and wounds (Duke and Wain, 1981; Kloss,
1939; Erichsen-Brown, 1979). One reported Mohawk antifertility concoction
contained milkweed and jack-in-the-pulpit, both considered contraceptive.
Dried and pulverized, a fistful of milkweed and three Arisaema rhizomes were
infused in a pint of water for 20 minutes. The infusion was drunk, a cupful an
hour, to induce temporary sterility (Erichsen-Brown, 1979). Cherokee used the
plant for backache, dropsy, gravel, mastitis, venereal diseases, and warts
(Hamel and Chiltoskey, 1975). In homeopathy, the rhizome is used as an
antiedemic and emmenagogue, in dropsy and dysmenorrhea (List and Horhammer,
According to Hager's Handbuch (List and Horhammer, 19691979), the latex
contains 0.11.5% caoutchouc, 1617% dry matter, and 1.23% ash. Also they
report the digitalis-like mixture of a- and b-asclepiadin, the antitumor
b-sitosterol, and a- and b-amyrin and its acetate, dextrose and wax.
The seed oil contains 4% paimitic-, 1% stearic-, 15% oleic-, 15%
11-octadecanoic-, 53% linoleic-, 1% linolenic; 10% 9-hexadecenic-, and 2%
9,12-hexadecadenic-acids. Condurangin has also been reported from the seed,
with at least 9 active cardenolids, among them uzarigenin, desgiucouzarin,
syriogenin, syriobioside; also xysmalogenin. The sprouts, eaten like
asparagus, e.g. among Yugoslavs, contains asclepiadin, nicotine,
b-sitosterol, a- and b-amyrin, and tannin.
Perennial herb with long-spreading rhizomes. Stems stout, erect, to 2 m tall,
with short downy hairs and milky juice; leaves opposite, oblong, rounded, 12.6
dm long, 0.41.8 dm broad, with prominent veins; upper surface smooth, lower
covered with short white hairs and strong transverse nerves. Flowers
sweet-smelling, pink to white, in large, many-flowered, axillary and apical
bell-like clusters; corolla lobes 69 mm long, hoods 34 mm high; follicle
grayish, hairy, with soft spiny projections, 13 mm high, slenderly ovoid, 2.5
3.5 cm thick. Seed brown, flat, oval, 6 mm long, 5 mm wide, with a tuft of
silky white hairs apically (Reed, 1970)
Reported from the North American Center of Diversity. Milkweed clones differ
substantially in height, earliness of maturity, length and circumference of
pods, as well as rubber content (Campbell, 1983). (2n= 22, 24)
Fields, pastures, roadsides, thickets, and woods in the eastern U.S., except
Gulf States, north on into Canada.
Estimated to range from Cool Temperate Dry to Wet through Warm Temperate Dry to
Wet Forest Life Zones, milkweed is estimated to tolerate annual precipitation
of 4 to 12 dm, annual temperature of 8 to 14°C, and pH of 5.5 to 7.3.
Since milkweed is usually harvested from the wild, there are few data dealing
with its cultivation. Campbell (1983) spaced his rows at 0.7 m apart, planting
his seed at the rate of 100/1.5 m, 2 cm deep, on an Aquic Hapludult pH 6.2
(2.0% organic matter). Seed dormancy is broken by removal of the seed coat or
with gibberellic acid or kinetin, which appear to counteract an inhibitor
located in the seed coat. Nondormant seeds can germinate at 1435°C and
apparently emerge best when planted 12 cm deep.
Shoots are harvested for forager food in spring, flower buds in midsummer,
green pods in late summer. Early fall, just before the pods dehisce, might be
the best time to harvest for floss. Those interested in floss may be surprised
to learn that only 13% of the flowers produce mature pods. According to
Gaertner (1979), "It was proven much more efficient to collect from the
abundant wild stands rather than to cultivate the plants."
Buchanan and Duke (1981) present a table showing an array of products available
from unimproved wild milkweed and a proposed developed milkweed.
Table. Possible products and yields from milkweed (Asclepias
syriaca) as a potential botanochemical crop.
*Based on dry weight and composi(ion of a typical wild plant assuming a plant
density of 107.635/ha.
|Unimproved "wild" variety*||Developed new crop**|
|Product ||Percent of dry plant ||Yield (kg/ha) ||Percent of dry plant ||Yield (kg/ha) ||Potential uses|
|Natural rubber ||1.6 ||197 ||4.0 ||897 ||Rubber-goods manufacture|
|Whole-plant (latex) oil ||4.1 ||505 ||6.0 ||1,345 ||Chemical intermediates|
|Polyphenol fration ||7.2 ||888 ||10.0 ||2,242 ||Chemical intermediate|
|Seedtriglyceride oil ||1.9 ||234 ||0.0 ||0 ||Edible oil|
|Seedextracted meal ||7.2 ||887 ||0.0 ||0 ||Foods and feeds (51% protein)|
|Extracted leafmeal ||16.0 ||1,973 ||33.0 ||,397 ||Feeds (20% protein)|
|Floss ||11.1 ||1,368 ||0.0 ||0 ||Insulating material|
|Bast fiber ||11.0 ||1,356 ||6.0 ||1,345 ||Premium paper-making, cordage|
|Woody fiberpod ||12.3 ||1,517 ||0.0 ||0 ||Paper- and board-making, fuel, furfural|
|Woody fiberstem shives ||27.6 ||3,404 ||41.0 ||9.190|
|Total ||100.0 ||12,329 ||100.0 ||22.416|
**Assumes two cuttings per season with the plant not allowed to seed, combined
genetic and agronomic improvement.
Source: Buchanan and Duke, 1981
Annual productivity ranges to ca 13 MT/ha according to the estimates of
Buchanan and Duke (1981), assuming a plant density of 107,635 kg/ha.
Agriculture Handbook 165 (1960) lists the following as affecting this species:
Alternaria sp. (leaf spot), Ascochyta asclepiadis (leaf spot),
Cercospora clavata (leaf spot), C. elaeochroma, C. hanseni, C.
illinoensis, C. venturioides, Diaporthe arctii (on stems), Didymella
cornuta (on stems), Diplodia asclepiadea (on stems), Erysiphe
cichoracearum (powdery mildew), Clomerella fusarioides (anthracnose,
leaf and stem blight), Phoma asclepiadea (stem blight), Phyllactinia
corylea (leaf spot), Phyllosticta cornuti (leaf spot),
Phymatotrichum omnivorum (root rot), Puccinis bartholomaei
(rust), P. seymouriana, Rhizoctonia solani (root rot), Scolecotrichum
asclepiadis (on leaves), Septoria asclepiadicola (leaf spot), ?S.
cryptotaeniae, S. incarnata, Sphaeropsis sphaerospora (on stems),
Stagonospora zonata (leaf spot), and Uromyces asclepiadis (rust).
Nematodes: Meloidogyne incognita, Pratylenchus penetrans (Golden, p.c.
1984). Mosaic virus and Yellows virus are also listed. According to Campbell
(1983), there is no evidence of major losses due to insects or disease;
however, aphid infestations and viral infections appear common, Aphis
nerii B. de F. is sometimes damaging in late summer around Beltsville. As
a weed, at densities of 11,000 to 45,200 plants/ha, milkweed reduces corn
yields 210%, sorghum 429%, and soybean 1219% (Cramer and Burnside, 1982).
Glyphosate at 2.2 kg/ha applied at early or late bud stage gave at least 70%
control (Cramer and Burnside, 1981).
Complete list of references for Duke, Handbook of Energy Crops
- Agriculture Handbook 165. 1960. Index of plant diseases in the United States.
- Buchanan, R.A. and Duke, J.A. 1981. Botanochemical crops. p. 157179. In:
McClure, T.A. and Lipinsky, E.S. (eds.), CRC handbook of biosolar resources.
Vol. II. Resource materials. CRC Press, Inc. Boca Raton, FL.
- Campbell, T.A. 1983. Chemical and agronomic evaluation of common milkweed,
Asclepias syriaca. Econ. Bot. 37(2):174180.
- Cramer, G.L. and Burnside, O.C. 1981. Control of common milkweed (Asclepias
syriaca). Weed Science 29(6):636640.
- Cramer, G.L. and Burnside, O.C. 1982. Distribution and interference of common
milkweed (Asclepias syriaca) in Nebraska. Weed Science 30(4):385388.
- Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
- Erichsen-Brown, C. 1979. Use of plants for the past 500 years. Breezy Creeks
Press. Aurora, Canada.
- Gaertner, E.A. 1979. The history and use of milkweed (Asclepias syriaca
L.). Econ. Bot. 33(2):119123.
- Hamel, P. and Chiltoskey, M. 1975. Cherokee plants and their usesa 400 years
history. Herald Publishing Co., Sylva, N.C.
- Hartwell, J.L. 19671971. Plants used against cancer. A survey. Lloydia 3034.
- Kloss, J. 1939. Back to Eden. Woodbridge Press Publishing Co., Santa Barbara,
- List, P.H. and Horhammer, L. 19691979. Hager's handbuch der pharmazeutischen
praxis. vols 26. Springer-Verlag, Berlin.
- Reed, C.F. 1970. Selected weeds of the United States. Ag. Handbook 366. USDA,
Last update December 29, 1997