Vinca, periwinkle , an evergreen twining shrub. It springs up in woodland in the temperate countries of Europe. It grows several slender, prostrate shoots from its base, which trail along the ground and spread extensively.

The leaves are small, oblong, and raised beneath by a bony midrib: they are shiny and the leaf margins are entire: they are of a pleasant but darkish green. The blue, rose-shaped flowers appear in spring. The cylindric, furrowed seeds are enclosed in coupled pods.

This shrub is quite widespread in several countries: it thrives in rich, damp soil and in the shade of trees. It propagates readily from cuttings and prostrate shoots which root as soon as they touch the soil. Its rapid growth and propagation soon cause it to invade a piece of land if it is left untended.

Periwinkles are of ornamental interest: when left to their own devices, they form carpets of greenery which are covered with flowers in March and April. One may make small hedgerows from them by supporting them with trellis-work, or leave them to twine round the stems of large trees in order to cover the trees with verdure.

source