Spanish Needles (Bidens Bipinnata) - Invasive or Inviting?

Yet another weedy, (sometimes considered invasive) "pest" of the Aster family, Spanish needles, Bidens bipinnata, grows in the south and central United States, and up much of the East Coast. But is that all the Spanish Needles plant is-a pest? First, to become better acquainted specifically with Bidens bipinnata, since there are other plants called Spanish needles, examine some lovely photos taken at the Parkville Nature Sanctuary in Platte County, Missouri, on the Missouri Plants website.

OK - Spanish Needles is a Pest

Though the plants are not without their charms, Spanish needles often grow uninvited in the garden. Since Spanish needle seeds remain viable for quite some time, it may be hard to eliminate the weed permanently. Worse, as the small yellow flowers convert into "fruits" (globes of needle-like seeds) in late summer to early fall, Bidens bipinnata becomes a pest, since its needles attach to socks and trousers, requiring hand-picking to remove. Chiefly these two factors are what causes us to look at Spanish needles with frowning faces. Really, though, how serious is this? To balance out our disdain, let us consider some of the plant's positive qualities and interesting features.

Spanish Needles - Food for Life

The Illinois Wildflowers website outlines the ecological importance of Spanish needles. Feeders include several varieties of bees, Syrphid flies, quite a few caterpillars, aphids, and beetles. Larger life-forms known to dine on Spanish needles include Ring-necked pheasant, Bobwhite, Wood Ducks and other birds, as well as rabbits. Is it important to feed these creatures?

Spanish Needles - Medicine

Important chemicals known as flavonoids are found in Bidens bipinnata as metabolites, and may be important anti-allergens, anti-inflammatories, anti-microbials, and even anti-cancer causing agents.¹ Flavonoids found in Spanish needle include "quercitin, hyperoside,quercitin-7-O-rhamnopyranoside, 6,7,3',4'-tetrahydroxyaurone, okani and luteolin."² Does this suggest Spanish needles are mere weeds, unworthy of our attention?

Design in Nature

Lastly, consider the matter of design in nature. This has become a hot topic in the late twentieth and early twenty-first century. Man, in effort to improve his inventions, has taken note of the engineering found in nature. Geckoes can adhere to nearly any known surface, barring Teflon®. Underwater vessels have been improved through the study of Porpoise skin. What will the design of Spanish needles tell us? Clearly, this plant, as well as all other plants, animals, and other objects found in nature, are not disposable, but have secrets to reveal, if we are only willing to seek and discover what they are.

^{1 See, for instance, the International Journal of Antimicrobial Agents, "Antimicrobial activity of flavonoids," vol. 26, Issue 5, pp. 343-356.- November 2005.
2 Anhui Medical and Pharmaceutical Journal, September 2009.}

References and Resources:

PAN-Germany - Spanish Needle

PubMed - "Protective effects of total flavonoids of Bidens bipinnata L. against carbon tetrachloride-induced liver fibrosis in rats." - J Pharm Pharmacol., Oct. 2008

Informa World - "New flavanone and chalcone glucosides from Bidens bipinnata Linn." - Journal of Asian Natural Products Research, Feb. 2005

WIT Journals Website - Design & Nature