The giant ranunculus (Ranunculus acris), commonly known as the tall buttercup, grows up to 3 feet in height. Considered a noxious weed in most locations of the United States, the plant spread from its native home in Europe. It grows in abundance in meadows, fields, coastal areas and forests.
Roots and Leaves
An upright perennial, the giant ranunculus spreads by seeds. A broadleaf plant, it grows off a large, fibrous root system. Several stems grow from each root crown to produce upright foliage that grows outward on stalks. The leaves sport three to seven lobed segments that are coarse in appearance with tiny hairs.
Flowers and Seeds
Small, yellow flowers appear from May to September. Pollination occurs from insects. Seeds occur in abundance. Seed dispersal occurs by birds who eat the seeds and than eliminate them still viable in new locations. The wind also aids in the spread of the plant. Seeds also often stick to clothing or tires.
Seeds begin to germinate in the spring. They require open soil. The plant grows best in moist, acidic soil conditions. Once established the plant can quickly take over pastures and meadows. It thrives in regions that have been overgrazed by livestock. Its rapid and aggressive spreading habits pose a serious threat to native plant life.
Giant ranunculus pose a serious threat to livestock due to its toxicity when grazed. It contains a toxin called protoanemonin. When consumed, the plant causes the livestock to suffer abdominal pain, mouth blisters, salivation and diarrhea. The taste of the plant is bitter and unpleasant so livestock will only graze it if they cannot find more suitable pasture plants to feed upon. If a large quantity of the plant is consumed it can be fatal.
Maintain a healthy pasture or lawn to prevent the seeds of the giant ranunculus from establishing. When the plants first establish themselves in the spring they can be controlled by promptly digging them up. Plowing also helps remove the plants from a field because it they do not tolerate tilling or cultivation. Broadleaf herbicides also work for control.