Bidens alba (Shepherd’s Needles)

This concludes my posting of wildflowers for the time being. I was interested in sharing these last two popular wildflowers form the Asteraceae family.
Bidens albaBidens alba (Shepherd’s Needles) Aka Spanish Needles, Romerillo, Beggarticks, or Butterfly Needles, is native to the neotropics, including the U.S., México, Guatemala, Honduras, Cuba, Dominica, Jamaica, Puerto Rico, Guayana Francesa, Guyana, Colombia, Venezuela and Perú. It belongs to the family Asteraceae, is most commonly known as Shepherd’s Needles, or Romerillo in Spanish.  Bidens means two-toothed, describing the two projections found at the top of the seeds, and alba refers to the white ray florets. The plant is also found in Africa and Asia, practically worldwide where it can spread. It can be seen in gardens, as well as road sides, mostly disturbed sites. Bidens alba is an annual or short-lived perennial, which is considered a weed in the United States. 

Bidens albaHardy to USDA Zones 7 – 9. Plants are killed to the ground by heavy frost, but come back quickly from roots and/or seeds when the weather turns warm. They have erect and ridged 1-4 ft (0.3-1.2 m) tall stems emerging from a strong taproot. In the tropics, shepherd’s needles stays green year round, but grows and flowers most actively when the weather is hot and rainfall is plentiful. Both butterflies and bees are highly attracted to this flower.  It is recommended that Shepherd’s needles be kept contained, as its needles, which are the seeds, can stick to clothing and spread easily. 

Spanish needles

The 0.25-0.5 in (0.6-1.3 cm) long ribbed seeds resemble flat black needles with 2-6 barbed hooks at each end. A single plant is capable of producing 3,000-6,000 seeds, which maintain viability for at least 3-5 years and germinate readily. The needles can embed themselves in one’s clothing every time you brush past the stems. (Image Wikipedia Commons)

Spanish Needles

Bidens alba (L.) DC. [as Bidens striata Schott ex Sweet], Curtis’s Botanical Magazine, vol. 59 [ser. 2, vol. 6]: t. 3155 (1832) [W.J. Hooker]



34 thoughts on “Bidens alba (Shepherd’s Needles)

    • I guess these are real nectar rich and more readily available than other ornamental plants. These are flowers in their purest form, perhaps how it was intended to be if it weren’t for humans


  1. I love these beautiful wildflowers. They make everything look just more beautiful and the shots you took of it are stunning as usual Maria. Love the beautiful bee on it. Thanks for sharing this lovely wildflower and the interesting info. 😀 ♥


    • Oh Roslyn, that one was not taken by me. I owe you that one. They mowed the entire place where I was observing these, and this plant is not seen that often around here, so I will post this seed capsule soon, taken by me. Thank you!


    • The seeds are a bit different than the previous flower. They don’t have a pappus that detaches itself and floats off in the air; they have these spines with two little barbles (bidens=2) which detach and can spread by air but they also depend on animals for dispersal. They are extremely bristly and sticky and travel great distances on just one animal. I don’t know if they are edible to birds, but their leaves host several butterfly species.


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