Dietmar Brandes (2005): Calotropis procera on <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Fuerteventura. http://www.biblio.tu-bs.de/geobot/fuerte.html Calotropis procera is a „spreading shrub or small tree to 4 m, exuding copious milky sap when cut or broken; leaves opposite, grey-green, large up to 15 cm long and 10 cm broad, with a pointed tip, two rounded basal lobes and no leaf stalk; flowers waxy white, petals 5, purple-tipped inside and with a central purplish crown, carried in stalked clusters at the ends of the branches; fruit grey-green, inflated, 8 to 12 cm long, containing numerous seeds with tufts of long silky hairs at one end” (KLEINSCHMIDT & JOHNSON 1977 cited after PIER species info). <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Originally from warm parts of Africa and Asia, this is now pantropical and in

ecological terms is regarded as an indicator of overgrazed land. I have seen it

growing extensively in Oman (Arabia), being one of the few plants that goats and

camels won't eat, and also in Antigua, in habitats degraded first by sugar cane

cultivation and now by cattle and goats.

There are no doubt many other places in the world where giant milkweed

abounds. It may be common and widespread but it is a magnificent shrub,

reaching 10 feet tall, with large silver-green leaves, clusters of waxy purpletipped

flowers, and inflated pale green seed pods. The pods split open when ripe

to release silk-tufted seed to the wind. The latex is poisonous, containing

digitalis-like compounds that affect the heart, and is used to make arrow poison.

Medicinally, the acrid sap latex is used to treat boils, infected wounds and other

skin problems in people, and to treat parasitic skin infestations in animals. It also

yields ash for making gunpowder, and extremely strong fiber. I have a young

plant grown from seed collected in Oman. It’s frustratingly slow! In warm parts of

the U.S. it would grow outside, but it might be worth checking first to see if it is

classed as an invasive species before doing so. – Deni Bown, Promising Plants

Presentation, 2003

The native range covers SW Asia (India, Pakistan, Afghanistan, Iran, Arabia, Jordan) and Africa (Somalia, Egypt, Libya, south Algeria, Morocco, Mauritania, Senegal). It occurs also on the Caribbean islands, in Central and South America and has been introduced to South Africa (Lebrun 1998). According to PIER species info Calotropis procera is also native in Thailand and Vietnam. The species is called “saharo-sindisch” by HOHENESTER & WELß (1993). Calotropis procera is assumed to be an environmental invasive (PIER species info). It escaped from cultivation in Hawai’i (WAGNER, HERBST & SOHMER 1999). Monarch watch pointed out, that this milkweed species is widely distributed throughout the Caribbean and that it is commonly harvested for its medicinal properties.

2. Calotropis procera on the Canary Islands

Calotropis procera is listed for Gran Canaria (e.g. SCHÖNFELDER & SCHÖNFELDER 1997). BRAMWELL & BRAMWELL (1987) call the introduction relatively recent. Neither KUNKEL (1977) nor HOHENESTER & WELß (1993 ), HANSEN & SUNDING (1993) or SCHÖNFELDER & SCHÖNFELDER (1997) report this species for Fuerteventura. Since our first visit to Fuerteventura in 1996 we found Calotropis procera running wild on the island (see BRANDES & FRITZSCH). ACEBES GINOVÉS et al. (2001) now report this species for Gran Canaria and Fuerteventura. At present Calotropis procera grows on Fuerteventura mainly in the region of the barranco de Giniginámar as well as in

"Spreading shrub or small tree to 4 m, exuding copious milky sap when cut or broken; leaves opposite, grey-green, large up to 15 cm long and 10 cm broad, with a pointed tip, two rounded basal lobes and no leaf stalk; flowers waxy white, petals 5, purple-tipped inside and with a central purplish crown, carried in stalked clusters at the ends of the branches; fruit grey-green, inflated, 8 to 12 cm long, containing numerous seeds with tufts of long silky hairs at one end"  (Kleinschmidt and Johnson, 1977; p. 147).

"Tall herb with sessile, obovate, glaucous leaves less than 2 times longer than broad; bud globular, flowers umbellate, violet; coronal spurs not recurved"  (Nicholson, 1991; p. 28).

"Shrubs, mostly less than 6 ft., but up to 15 ft.; similar to C. gigantea, but leaves oblong to elliptic, corolla usually about 1 in. across with lobes more erect, corona lobes glabrous or pubescent, and follicle 4-5 in. long"  (Bailey and Bailey, 1976; p. 206).

Propagation:  "Seeds spread by wind and water over large distances.  Local stands increased in size by suckering."  (Smith, 2002; pp. 28-29).

Native range:  India to Iran and Africa.

Presence:

Comments:  Reported as escaped from cultivation in Hawai‘i (Wagner et al., 1999; p. 238). A declared noxious weed in Western Australia and the Northern Territory (Smith, 2002; pp. 28-29).

Control: 

Physical:  "Manual removal should aim at removing as much of the taproot and lateral roots as possible to prevent resprouting".

Chemical:  "Actively growing seedlings and larger plants can be treated with a mixture of 2,4-D and picloram.  In the case of mature plants, herbicides may also be applied to the basal bark"  (Weber, 2003; p. 81).