Family: Buttercup Family (Ranunculaceae)
Origin and Distribution: Since its introduction from Europe, creeping buttercup has spread throughout the northern U.S. and Canada, and is especially abundant in the Pacific Northwest. This weed is found in poorly drained areas including marshes, meadows, pastures, roadsides, and lawns, and in disturbed sites such as gardens and fields used to grow grains or forages. Creeping buttercup grows well in heavy clay and muck soils, but can thrive in sand or gravel if moist. It is rarely encountered on light, well-drained soil.
Plant Description: Creeping buttercup is a low-growing, rosette-forming, spreading perennial. It is characterized by 3-parted leaves and creeping horizontal stems (stolons) that root at the nodes to form new rosettes. This species reproduces primarily by stolons, but can also reproduce by seeds. Because of its spreading, strawberry-like growth habit, creeping buttercup can rapidly form large patches.
- Root system - Many stout roots are produced by the rosette. Roots can form at the nodes of horizontal stems (stolons).
- Seedlings & Shoots - The 2 seed leaves (cotyledons) are smooth, dark green, and oblong. The true leaves of young plants are triangular and shallowly lobed, and form a rosette.
- Stems - Tough, non-flowering stems grow horizontally along the ground. Flowering stems grow upright (1/2 to 1 foot tall, sometimes up to 2 feet). Both stem types are usually notably hairy, but can sometimes vary from smooth to only somewhat hairy.
- Leaves - Leaves are alternate (1 per node), hairy, and dark green, sometimes with pale spots. They are borne on long, hairy leaf stalks (1/2 to 10 inches long). Leaves are triangular or heart-shaped in general outline (1/2 to 2 1/2 inches long, 3/4 to 3 inches wide), and are divided into 3 segments like a three-leaf clover. Each segment is deeply lobed and toothed. The middle leaf segment has a distinct stalk, while the 2 side segments may or may not have a short stalk. Leaves in the upper portion of flower stems attach directly to the stem, and tend to be narrow and unlobed.
- Flowers - Showy, 1-inch wide flowers are produced singly or sometimes in clusters along an erect flowering stem. Each flower is borne on a long, hairy stalk (3/4 to 4 inches long), and is composed of 5 to 7 petals. Petals are glossy yellow, wedge-shaped 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 & Seeds - Seeds are produced in a spherical seedhead. Each seedhead is composed of 20 to 50 seeds. Seeds are light to dark brown, flattened, egg-shaped in outline, and 1/8 inch long, with a short hooked tip.
Similar Species: Creeping buttercup may be confused with other buttercup species. Tall buttercup (Ranunculus acris) can be distinguished from creeping buttercup by its upright growth habit. In addition, the leaves of tall buttercup are deeply lobed and toothed, but are not divided into 3 distinct segments like the leaves of creeping buttercup. Bulbous buttercup (Ranunculus bulbosus), a perennial, has 3-parted leaves like creeping buttercup, but has an erect growth habit. 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 annual or biennial, and can be distinguished from creeping buttercup by its erect growth habit, much smaller flowers, smooth leaves and stems, drooping sepals, and very shallowly lobed basal leaves.
Biology: Creeping buttercup overwinters as a rosette or seed. In the spring, overwintered rosettes produce new leaves, and seeds may germinate. Horizontal creeping stems (stolons) develop from leaf axils. Stolons root at the nodes to form new rosettes that are genetically identical to the parent. Stolon development continues throughout the summer, but by late summer or early fall, the stolons connecting parent and daughter rosettes wither. Because of this growth habit, creeping buttercup can rapidly spread to form large patches.
Flowering occurs from April to August. One to five glossy, golden yellow flowers are produced on an erect flower stem. Flowers are pollinated by a wide variety of insects, and 20 to 50 single-seeded fruits are produced in a spherical seed head. These seeds are spread by wind, birds, rodents and humans. Seeds can remain viable in the seedbank for several years and tend to be highly dormant, with only a few seeds germinating in a given spring.
Because of its low growth form, creeping buttercup escapes control by mowing. However, established plants can be controlled by repeated tillage. This species persists in no-till and perennial crops such as strawberry and asparagus. Its growth habit and flowering pattern resemble that of strawberry, a crop in which it is particularly troublesome.
Toxicity: Creeping buttercup contains a bitter, irritating oil called protoanemonin that is toxic to grazing livestock (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 to 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 creeping 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 golden yellow color of the flower.
- The common name 'crowfoot' refers to the resemblance of the leaf to a large bird’s foot.
- The genus name, Ranunculus, means 'little frog', and likely refers to the plant's affinity for bogs and other moist places.