Origin:
Introduced from Europe and now found throughout the United States and southern Canada.
Biology:
A summer annual that reproduces by seeds. Seeds are prickly and spiny and easily cling to clothing or animal fur, allowing dispersal over wide areas. Seeds can germinate throughout the warm time of the year. Plants have a preference for very wet soils and commonly line creek banks. However, they also tolerate other conditions and may be found in landscape, roadsides, or empty lots.
Identification:
Mature plants grow very tall on long, slender stalks, reaching up to 5 feet in height. One or more stems arise from the base and may branch multiple times near their tops. Stems are smooth or slightly hairy and have a 4-sided appearance. Leaves are opposite and compound, being divided into 3 to 5 large leaflets with a single terminal leaflet. Margins of the leaflets are strongly toothed and the leaf has a long stalk over 2 inches in length. Flower heads occur at the end of short or long stalks that arise from the axils of the leaves. The flowers are small, and the surrounding bracts are actually longer than the flowers, surrounding them in a cup-like fashion. The ray flowers are yellow and the disc flowers are brownish-yellow, and some flower heads may have only the dull disc flowers. The seeds are very distinctive, being large and flattened, and with 2 long, barbed spines or horns on one end. This distinguishes them from Nodding beggarticks which has seeds with 4 spines.
Characteristicts Important to Control:
Physical removal of individual plants should be attempted and is successful, but control should be done prior to seed maturation to avoid seeding the soil. Very moist soils encourage the growth of the plant.
