Common Periwinkle is an introduced mildly invasive perennial trailing vine without tendrils. Its stems lie prostrate on the ground forming a dense mat. Shoots are slender, green and root at the nodes.
The leaves are firm, glossy ever-green, opposite, elliptical to ovate, up to 1 inch long and half as wide. The tips are blunt to acute, the base tapered to a short stalk. Margins are smooth and the area of the midvein is a lighter color. The underside is slightly paler in color but glossy also.
Inflorescence: Flowers are solitary, stalked and arise from the leaf axil.
The flowers are about 1 inch wide, with bluish-purple corollas that form a funnel shape with the 5 petals spreading outward from the top of the funnel. The spreading parts of the petals are wedge shaped, broadest at the tip, with fused bases forming the funnel. They are slightly asymmetrical producing a pinwheel effect as though the corolla were rapidly rotating about the center and suddenly stopped. The inside of the corolla has fine hair at the throat, the outside is smooth. Inside the throat of the corolla but not exserted are five stamens with green filaments and yellow anthers. Stamens are opposite the petals and joined together in the throat of the corolla with the anthers folding around the single green style with a stigmatic disc a the top that has fine white hair but the actual stigma lies on the underside of the disc preventing self fertilization. The outer short green calyx has five long pointed lobes.
Seed: Fertile flowers can produce a pair of one inch long pods (follicles) that contain a few dark seeds but most flowers do not produce the pods as the plant reproduces mostly from the root system.
Habitat: Common Periwinkle grows from a woody rhizomatous root system, which produces underground runners and forms a dense mat via the runners and rooting along those stems. Thus, in the home garden it may require some control. It tolerates a variety of soils from moist to slightly dry conditions. It does well in light shade or partial sun but not full sun. In the Wildflower Garden, the plant is a ground cover on Violet Way in the Woodland Garden, extensively covering the hillside. As the plant only grows from 3 to 6 inches in height, it makes a good ground cover for shady areas under trees. Popular for many years, the plant is an escapee from cultivation and in some states such as Wisconsin and Tennessee is considered in the wild to be weedy and invasive.
Names: The genus name, Vinca, is from the Latin vincio, meaning 'to bind', and referring to the shoots that can root. The species, minor, simply means the smaller, used when there is a similar species that is larger - in this case Vinca major, the Bigleaf Periwinkle. The author name for the plant classification, 'L.', refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. Vinca minor is in the same plant family as the Milkweeds.
The common name of 'periwinkle' is also derived from the Latin root. In old Anglo-Saxon it was 'parwynke,' and sometimes called 'Joy of the Ground' all referring to the rooting stems. The other old common name of 'running myrtle,' apparently comes from the Myrtle plant of the Mediterranean which is evergreen and has shiny leaves. Our species here, V. minor has shiny leaves and is evergreen, but creeps along the ground as it roots. The word 'running' is frequently applied to creeping plants - hence 'running myrtle.'
Comparisons: Vinca minor is the only species of Vinca found in Minnesota, thus V. major will not be encountered here.
Above: Low growing Vinca minor growing among other plants. Drawing courtesy Kurt Stüber's Online Library.
Below: The glossy leaves are evergreen, the petals of the corolla are slightly asymmetrical producing a pinwheel effect.
Below: 1st photo - The throat of the corolla has a ring of fine hair that surrounds the five stamens (placed opposite the petals) whose yellow anthers join together around the single style. 2nd photo - The green calyx of the flower is small and short with 5 pointed lobes from which rises the funnel shaped corolla.
Below: 1st photo - The underside of the leaf is slightly paler in color than the top but glossy also. 2nd photo - A dense mat of plants can be formed via the above ground runners which root along those stems.
Below: Common Periwinkle makes an excellent ground cover for a shady area as this hillside along Violet Way in the Garden indicates.
Notes: Common Periwinkle is not indigenous to the Garden. It was listed on Martha Crone's 1951 inventory of plants in the Garden at that time. She reported planting it in 1947, '48 and 1956, and has been in the Woodland Garden ever since. When Martha Crone retired as Curator she wrote in the Autumn issue of The Fringed Gentian™ [Vol. 6, no. 4] of what she considered her notable successes in the Garden and one listed as outstanding was the patch of Running Myrtle. The plant is widely distributed in the eastern half of the United States and Canada and less so in the western half. In is not native in any State, but native to Europe.
V. minor is common in Great Britain from which the introduction to North America probably occurred. The plant was used in folk medicine for treating hemorrhages. It has one enemy however - it is subject to a stem blight (Phoma exigua var. exigua) a fungus that kills new stems soon after spring growth.
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.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"