Ohio Perennial and Biennial Weed Guide

Family:

Buttercup Family (Ranunculaceae)

Other Names:

blister plant, butter flower, butterrose, common buttercup, crazy weed, field buttercup, gold cup, meadow buttercup, tall crowfoot, tall field buttercup, upright meadow crowfoot.

Origin and Distribution:

Since its introduction from Eurasia, tall buttercup has become widespread throughout the U.S., excluding an area between central Montana and eastern Minnesota. It can be found in a variety of habitats, including wet lowlands and rich woodlands and is a common weed in pastures, meadows, and along roadsides. It usually does not persist in cultivated fields. Tall buttercup prefers heavy, moist soils.

Plant Description:

Tall buttercup is a perennial weed characterized by erect stems and deeply lobed leaves. This species reproduces only by seeds.

• Root System:

  Tall buttercup produces a short, thick rootstalk with many fibrous, coarse, spreading roots.

• Seedlings and Shoots:

  The 2 seed leaves are egg-shaped (about 1/2 inch long) and have 3 to 5 noticeable veins. Young plants form a rosette. The first true leaves are hairy, round to heart-shaped in general outline, and shallowly lobed and toothed. True leaves have long leaf stalks that are hairy except at the base.

• Stems:

  Stems are erect, hairy, branched in upper portion, and 1 to 3 1/2 feet tall. A single root crown generally produces several stems in a cluster.

• Leaves:

  Leaves are produced both at the base of the plant and alternate (1 per node) along the stem. Leaves are softly hairy, triangular to round in general outline (1 to 4 inches wide), and deeply cut into 3 to 5 lobes. The lobes are coarsely toothed and radiate from a common point like fingers of a hand. Basal and lower stem leaves have long, hairy stalks and resemble middle leaves, which attach directly to the stem. Upper leaves are smaller and have fewer lobes and teeth.

• Flowers:

  Flowers (1 inch wide) are borne on long stalks in branched clusters at the tops of stems. The 5 to 7 petals are glossy yellow (sometimes cream), and about 1/2 inch long. Directly below the petals are 5 hairy, green floral leaves (sepals) that are much shorter than the petals.

• Fruits and Seeds:

  Numerous seeds are clustered in a round seedhead. Seeds are dark brown, flattened, egg-shaped in outline, and 1/8 inch long, with a short, slightly curved tip.

Similar Species:

Tall buttercup may be confused with several other buttercup species. Creeping buttercup (Ranunculus repens) can be distinguished from tall buttercup by its distinctly 3-parted leaves, and horizontal growth habit with creeping stems that root at the nodes. Bulbous buttercup (Ranunculus bulbosus), an upright perennial, also has distinctly 3-parted leaves. In addition, the stem of bulbous buttercup is swollen at the soil surface to form a bulb-like base and the sepals below the flowers droop towards the stem. Smallflower buttercup (Ranunculus abortivus) is an upright annual or biennial, and can be distinguished from tall buttercup by its much smaller flowers, smooth leaves and stems, drooping sepals, and very shallowly lobed basal leaves.

Biology:

Tall buttercup blooms from late May to September. Flowers are pollinated by a variety of insects. This weed will not survive cultivation and prefers moist soil conditions. Therefore, plowing a field or meadow and/or improving drainage in an area will help control the weed.

Toxicity:

Tall buttercup contains a bitter, irritating oil called protoanemonin that is toxic to grazing livestock and other animals (especially cattle). Toxicity varies with plant age, growing conditions, and freshness of foliage. The toxic oil is released when fresh leaves and stems are grazed, causing irritation and blistering of the skin and the lining of the mouth and digestive tract. In severe cases, gastric irritation progresses to paralysis, convulsions, and death. Because the fresh foliage of tall buttercup is distasteful, animals tend to avoid it if better forage is available. The toxic oil evaporates quickly, so hay containing dried buttercup foliage is not harmful.

Facts and Folklore:

• The common name 'buttercup' was derived from the yellow color of the flower. It was also believed that the richness of butter's yellow color was the result of the number of buttercups in the pasture; however, this was only a myth since tall buttercup is so bitter that cattle avoid eating it.

• The common name 'crowfoot' refers to the resemblance of the leaf to the foot of a large bird.

• The common name 'blister plant' comes from the blistering that occurs in the mouth and intestinal tract when cattle eat the plant.

• The genus name, Ranunculus, means 'little frog', and likely refers to the plant's affinity for bogs and other moist places.

• The species name, acris, means 'bitter', describing the very pungent taste of tall buttercup foliage.

• According to superstition, holding a tall buttercup flower against one's neck on the night of a full moon, or simply smelling the flower, causes insanity, hence the folk name 'crazyweed'.

• It is also customary to hold the flower under one's chin; if the skin shines yellow then the person loves butter.

• Flowers tend to track the daily movement of the sun in the sky.

• Beggars used to blister their skin purposefully with buttercup juice to arouse the sympathy of passersby.

• Fishermen of the 1800's poured buttercup tea on the ground to bring worms to the surface.