‘Vinca’ or ‘Periwinkle’ as the plant genus is commonly known, is a genus consisting of six species in the plant family ‘Apocynaceae.’ This seemingly humble plant can grow at a colossal pace, and is the favourite groundcover of many a gardener.
Periwinkle is a trailing plant, sending out slender stems of about 1-2 meters long. These stems frequently take root when coming into contact with the ground, and can easily divide and dominate the landscape. Stems also generally don’t grow any more than 70 centimetres above the ground.
The plant is perennial, retaining its glossy leaves throughout winter, these leaves being arranged in an opposite arrangement. The length and breadth of leaves are dependent on the species of Periwinkle in question, with species like ‘Vinca minor’ having small, dainty leaves, as opposed to larger leaves in ‘Vinca major.’ Generally, however, leaves are between 1 and 9 centimetres long, and between 0.5 and 6 centimetres broad. The plants are evergreen, retaining their foliage throughout the year, except for the deciduous ‘Vinca herbacea.’
The most commonly cultivated species in the genus are arguably ‘Vinca major,’ and ‘Vinca minor.’ These two varieties of Periwinkle are grown extensively as ornamental groundcovers. ‘Vinca major,’ the ‘greater Periwinkle,’ is indigenous to southern Europe and north-eastern Turkey, found in such areas as Spain and southern France. Its leaves are 3-9 cm long and 2-6 cm broad, with stems reaching as far as 5 metres around the plant. The leaves also have a leathery texture, with a hairy margin and petiole. These characteristics aid to minimise loss of water through evapo-transpiration.
‘Vinca minor,’ or the ‘lesser Periwinkle,’ is native to central and southern Europe, as well as south-western Asia. Leaves are 2-4.5 cm long and 1-2.5 cm broad, sharing the same characteristics as the greater Periwinkle, but lacking in a hairy margin and petiole.
Other, less prominent species, include ‘Vinca difformis,’ or the ‘Intermediate Periwinkle,’ native to Western Europe; ‘Vinca herbacea,’ or the ‘Herbaceous Periwinkle,’ native to eastern and south-eastern Europe and also south-western Asia, and also ‘Vinca erecta’ and ‘Vinca pubescens.’ There are also many cultivars available.
Periwinkle is a flowering plant (an Angiosperm), producing masses of delicate violet (and occasionally white) flowers throughout the year, primarily from early spring through autumn. Flowers are funnel shaped (salver form), with five petals, and about 2.5–7 cm broad. Oddly, the plant rarely ripens its seed, suggesting that it is not truly indigenous, although it does ripen its seed in more southern areas. The plant rather chooses to propagate itself through long, trailing stems that take root when coming into contact with the ground. Through its ability to speedily multiply, Periwinkle is considered to be a mildly invasive species in areas where it is introduced, such as coastal California in the USA.
Periwinkle has long been used for medicinal purposes. The plant and its components have been used to aid in the treatment of: cancer, diabetes, haemorrhages, digestive problems, eye irritations, etc. The plant also contains the alkaloid “vincamine” (along with at least 86 other alkaloids), which is used as a cerebral stimulant and vasodilator.
These uses, combined with the already discussed commercial use as a ground cover (and the use of stems in basket making), undoubtedly make Periwinkle an infinitely precious herb.