Horticulture/Vinca

Vinca Vinca major1.jpg Vinca Apocynaceae Perennials Insects Toxic if eaten. Vinca is a genus of five species of in the family ../Apocynaceae/, native to Europe, northwest Africa and southwest Asia. The common name, shared with the related genus ../Catharanthus/, is Periwinkle.Pharmacognosy of Vinca (Periwinkle) Description They are trailing vines, subshrubs or herbaceous, and have slender trailing stems 1-2 m 3-6 feet long but not growing more than 20-70 cm 8-30 inches above ground; the stems frequently take root where they touch the ground, enabling the plant to spread widely. The leaves are opposite, simple broad lanceolate to ovate, 1-9 cm 1/4-3.5 inches long and 0.5-6 cm 1/4-2.25 inches broad; they are evergreen in four species, but deciduous in the herbaceous V. herbacea, which dies back to the root system in winter. The flowers, produced through most of the year, are salverform (like those of ../Phlox/), simple, 2.5-7 cm 1-3 inches broad, with five usually violet (occasionally white) petals joined together at the base to form a tube. The fruit consists of a group of divergent follicles; a dry fruit which is dehiscent along one rupture site in order to release seeds. Species The two most commonly grown species are ../Vinca major/ and ../Vinca minor/ Uses Two species, the Small Periwinkle V. minor and the Large Periwinkle V. major, are very popular ornamental plants in gardens, grown for dense evergreen ground cover and their delicate violet flowers. V. major has broader leaves with a hairy margin and larger flowers, is less cold hardy, and has twice as many chromosomes as V. minor. A variegated selection of V. major is commonly cultivated. Both species are considered invasive weeds in parts of the United States and Australia. They do not respond to common herbicides and require hormone based sprays to control. This plant was formerly used in homeopathy for catarrh and dyspepsia but due to the nature and effects of the alkaloids vincamine, isovincamine and vincamidine, it is rarely used. The chemotherapy drugs vincristine and vinblastine are derived from this plant. Maintenance Remove any leaf cover in the fall to prevent fungal problems. Propagation Propagated by cuttings. Pests and diseases ../Blight/ ../Botrytis cinerea/ ../Canker/, ../Dieback/ Phoma exigua var. exigua (asexual stage Diaporthe vincae) ../Leaf Spots/ Alternaria Colletotrichum Macrophoma vincae Phyllosticta Phyllosticta minor Phyllosticta vincae-majoris ../Root Rot/ ../Pellicularia filamentosa/ ../Nematodes/ ../Meliodgyne haple/ ../Xiphinema americanum/ ../Aphids/ Green Peach Aphid: ../Myzus persicae/ Oleander Aphid: ../Aphis nerii/ Crescent-marked Lily Aphid: ../Neomyzus circumflexus/ ../Scales/ Brown Soft Scale: ../Coccus hesperidum/ ../Hoppers/ Aster Leafhopper: ../Macrosteles facifrons/ ../Whiteflies/ Silverleaf Whitefly: ../Bemisia argentifolii/ ../Mealybugs/ Citrus Mealybug: ../Planococcus citri/ ../Earwigs/ European Earwig: ../Forficula auricularia/ ../Thrips/ Flower thrips: ../Frankliniella thricti/ Gallery References Flora Europaea: Vinca Virtual Flowers Vinca Blamey, M., & Grey-Wilson, C. (1989). Flora of Britain and Northern Europe. Hodder & Stoughton. Huxley, A., ed. (1992). New RHS Dictionary of Gardening 4: 664-665. Macmillan. Pirone Pascal P. Diseases & Pests of Ornamental Plants Fifth Edition 1978 John Wiley & Sons, New York 530-531 Cranshaw Whitney Garden Insects of North America: The Ultimate Guide to Backyard Bugs 2004 Princeton University Press 625