Monday, September 28, 2015
Spanish Needles - Bidens bipinnata
Like its more common cousin, Spanish needles is an upright annual and forms a noticeable taproot. The stems reach a mature height of about 3 feet in late summer. As the Latin name suggests, the leaves appear to be bipinnately compound - though they are, in fact, simple, but deeply dissected. They are opposite each other on the stem and several inches long near the base of the plant.
Flowering occurs in late summer and fall. The plants above were photographed along a roadside in Jefferson County on September 26, 2015. Many flowers are produced at the tips of the stems, they are less than 1/2 inch across, and composed of a set of bright yellow ray petals encircling a center of yellow disk flowers. Once flowering ends, the ripened fruit is an elongated collection of 4-barbed achenes.
Spanish needles attracts pollinators, but has few aesthetic qualities that would make it suited for a home landscape. As such, it is a plant most likely to be encountered on a hike along disturbed edges in full to partly sunny locations. Just watch that you don't take some home with you, hooked tightly to your socks or pant legs.