Rough Cinquefoil is an erect introduced and naturalized forb that can be annual, biennial or a short lived perennial. It begins life with a basal rosette, later sending up a flowering stalk from 1 to 3 feet high. The stem is leafy, hairy, and usually branched near the top, green initially then turning to a dull reddish-purple.
Leaves, both basal and on the stem, are slightly hairy on top, more so on the underside, are 3-parted with each elliptical to oval leaflet 2 to 3 inches long, tapering to the base, with slightly rounded edges on the teeth, some of which are double. The basal leaves have long hairy leaf stalks while the stem leaves are alternate with shorter stalks. The uppermost leaves are stalkless.
The inflorescence is a tight branched cluster (a cyme) or clusters, as several may form on the upper branches. Solitary flowers also occur from the upper leaf stalks.
Flowers: Each pale yellow 5-parted flower is only 1/3 to 1/2 inch wide with gaps between the 5 petals through which appear the 5 green hairy calyx lobes (sepals) that are longer than the petals. Just below the sepals are 5 still longer green spreading bracts that are more triangular shaped. The flower has between 10 and 20 stamens with yellow filaments and anthers in a circular pattern around a dome shaped center receptacle containing the thread-like styles of the numerous pistils. Flowers do not all bloom at once, giving an extended bloom period of a month or more for the plant.
Seed: In fertile flowers, the long calyx lobes (sepals) fold upward and over the flower head forming a cone like protective structure until the seeds (dry flattened achenes without a pappus) are mature and are scattered from the plant by wind action on the tall stem. Regeneration is from re-seeding.
Habitat: Rough Cinquefoil is found in many sites, from dry to slight moist soils, in full sun to partial shade. As it regenerates from seed, it usually takes hold along edgeways where seedlings are not crowded out by more vigorous perennial vegetation.
Names: The genus name, Potentilla, is from the Latin word potens, meaning 'powerful' and refers to the medicinal power of some species of the genus which have medicinally properties. The species name, norvegica, means "of Norway" and perhaps is a reference to whose settlers brought the plant to North America. The old common name of Strawberry Weed is due to the similarity of the leaves of a young plant to the common strawberry.
Comparisons: Another non-native that is similar to this species is P. recta, the Rough-fruited Cinquefoil. But there the lower leaves are 5 to 7 parted and the flower sepals and bracts are much shorter than the petals.
Above: - Note the several cymes branching at the top of the dull reddish stem. Leaves: 1st photo is a long stalked basal leaf. 2nd photo - note the hair on the underside especially on the mid-vein and the double-teeth.
Below: The petals have clawed bases, tips are not notched. Between them appear the slightly longer hairy green calyx lobes (the sepals), and behind the petals are the longer hairy bracts.
Below: 1st photo - A typical 3-parted upper stem leaf without a stalk. 2nd photo - All the upper parts have long fine hair - the stem, the leaves, the bracts and the sepals.
Notes: Rough Cinquefoil is indigenous to the Garden. Eloise Butler first noted in her Garden log on June 26, 1910. It was still in the Garden at the time of the 1986 census but has since gone missing. The plant is widespread throughout North America having been introduced to the continent during the early colonial period. It found in all Canadian Provinces and all US States except Louisiana, Mississippi and Florida. Within Minnesota it has been found in the vast majority of the counties with exceptions widely scattered. It is found in most metro counties. It has been in the state so long that most references consider it to be native, although it is a native of Eurasia. There are 19 Cinquefoils that have been found in Minnesota of which 3 are introductions. Four of those have not been collected in many years and may not be extant.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"