medicinal plants

Periwinkle.

Description and Natural History of the Periwinkle Catharanthus roseus is known as the common or Madagascar periwinkle, though its name and classification may be contradictory in some literature because this plant was formerly classified as the species Vinca rosea, Lochnera rosea and Ammocallis rosea. Furthermore, lesser periwinkle (Vinca minor) may also be called common periwinkle. Both species are also known as myrtle.
In any case, this periwinkle is a perennial, evergreen herb in the dogbane family (Apocynaceae) that was originally native to the island of Madagascar. It has been widely cultivated for hundreds of years and can now be found growing wild in most warm regions of the world, including the Southern U.S. The plants grow one or two feet high, have glossy, dark green leaves (1-2 inches long) and flowers all summer long. The blooms of the natural wild plants are a pale pink with a purple "eye" in their centers, but horticulturists have developed varieties with colors ranging from white to hot pink to purple.
The plant has historically been used to treat a wide assortment of diseases. It was used as a folk remedy for diabetes in Europe for centuries. In India, juice from the leaves was used to treat wasp stings. In Hawaii, the plant was boiled to make a poultice to stop bleeding. In China, it was used as an astringent, diuretic and cough remedy. In Central and South America, it was used as a homemade cold remedy to ease lung congestion and inflammation and sore throats. Throughout the Caribbean, an extract from the flowers was used to make a solution to treat eye irritation and infections.
It also had a reputation as a magic plant; Europeans thought it could ward off evil spirits, and the French referred to it as "violet of the sorcerers."
Western researchers finally noticed the plant in the 1950's when they learned of a tea Jamaicans were drinking to treat diabetes. They discovered the plant contains a motherlode of useful alkaloids (70 in all at last count). Some, such as catharanthine, leurosine sulphate, lochnerine, tetrahydroalstonine, vindoline and vindolinine lower blood sugar levels (thus easing the symptoms of diabetes). Others lower blood pressure, others act as hemostatics (arrest bleeding) and two others, vincristine and vinblastine, have anticancer properties. Periwinkles also contain the alkaloids reserpine and serpentine, which are powerful tranquilizers.
Because the alkaloids in this plant can have serious side effects such as nausea and hair loss, it is not recommended that people attempt to medicate themselves with periwinkles.
For more information, visit:
HREF="http://www.lycaeum.org/graphics/organics/html/catharanthus.html">Catharanthus
Growing Instructions -->
Periwinkle Diseases
References:
Dobelis, Inge N., ed. 1989. Magic and Medicine of Plants. Pleasantville, NY, Reader's Digest Books.
Heywood, V.H., ed. 1993. Flowering Plants of the World. New York, NY, Oxford University Press.
Simpson, Beryl Brintnall and Molly Conner-Ogorzaly. 1986. Economic Botany: Plants in Our World. New York, NY, McGraw-Hill Publishing Co.
Periwinkle
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Periwinkle is also called vinca or myrtle. Of the 12 species of periwinkle, two are popular ground- covers. All species have opposite leaves and single flowers. The perennial periwinkle should not be confused with the bedding plant, Madagascar periwinkle (Catharanthus roseus).
DESCRIPTION
Periwinkle (Vinca minor) is an excellent evergreen groundcover with dark green foliage. Oblong to ovate leaves are opposite, simple, ½ to 2 inches long, glossy, with a short petiole. They exude a milky juice when broken. Flowers are purple, blue or white depending on the cultivar. Plants bloom in April and sometimes again in the fall. Vinca minor grows about 6 inches tall, spreading in all directions by sending out long trailing and rooting shoots, which make new plants.
Vinca major or large periwinkle is a larger, more aggressive species than V. minor. Leaves are up to 3 inches long. The blue, funnel-shaped flowers are 1 to 2 inches in diameter. They are borne in abundance in early spring and sporadically throughout the summer. Large periwinkle spreads rapidly and will mound up to 2 feet. Non-flowering stems root at the tips where they touch the ground.
LANDSCAPE USE
The trailing, arching stems that root where they touch the soil make these evergreen plants useful as groundcovers, for erosion control on banks, or for cascading from window boxes or planters. Periwinkle grows well under trees and shrubs, on shaded slopes or on the north side of buildings. Spring-flowering bulbs interplanted with periwinkle will lend color and interest to the groundcover planting. Daffodils are particularly well-suited since they bloom with periwinkle and do not require frequent division.
CULTIVATION
Periwinkle prefers shade but will grow well in full sun. The foliage color is richer green in partial shade, but more flowers are produced in the sun. Rooted cuttings or established plants are normally spaced from 12 to 18 inches apart. At a 6-inch spacing periwinkle will completely cover an area in one year. Plant whenever the soil is workable and provide sufficient water, especially when planting in summer. Weeding and mulching are required on a regular basis until the groundcover fills in the planted area. Periwinkle prefers moist, well-drained soil, abundantly supplied with organic matter, but it is tolerant of a wide variety of soil conditions. Fertilize only when necessary, preferably in the spring with a complete fertilizer such as 10-10-10 at a rate of 6 to 8 pounds per 1,000 square feet. Occasionally shear plants close to the ground to encourage new growth. Propagate by taking tip cuttings of non-flowering stems in late spring or divide throughout the season.
CULTIVARS OF PERIWINKLE
‘Alba’ has white flowers.
‘Atropurpurea’ has purple flowers.
‘Bowles Variety’ has blue flowers and grows vigorously in clumps.
‘Variegata’ has blue flowers and leaves variegated with rich yellow.
‘Flore Pleno’ has double, purple flowers.
‘Alboplena’ bears white, double flowers.
‘Jekyll’s White’ has single, pure white flowers and is more floriferous than ‘Alba.’
‘Sterling Silver’ bears dark blue flowers and foliage with white margins.
CULTIVARS OF LARGE PERIWINKLE
‘Alba’ has white flowers
‘Pubescens’ bears more pubescent leaves than the species and red-purple flowers with narrow petals.
‘Reticulata’ has foliage netted with yellow lines.
‘Variegata’ has creamy white blotches on the leaves. Flowers are blue and plants are sometimes known as ‘Elegantissima.’
PROBLEMS
Periwinkle is susceptible to dieback (plants wilt and "die back" to the ground), caused by fungal diseases. Cankers, which are sunken, woundlike lesions, may be visible on the stem near the groundline. Fungal leaf spots occasionally occur and look like brown circular-to-oval spots on the leaves. Infected leaves should be sheared off and discarded. To reduce fungal infection, avoid overhead irrigation. Chemical control is seldom necessary.
Prepared by Marjan Kluepfel, HGIC Information Specialist, and Bob Polomski, Extension Consumer Horticulturist, Clemson University.
This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed. (New 6/99).

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