While annual vinca, or Madagascar periwinkle (Catharanthus roseus), is best grown from seed, perennial littleleaf periwinkle (Vinca minor) and common periwinkle (Vinca major) easily grow from cuttings.
Vinca produces two types of stems. The upright stems sport flowers while the non-flowering horizontal stems spread along the ground. The horizontal stems often form roots where the leafy nodes touch the ground. For a quick cutting, find a rooted node and clip the stem leading back to the parent plant. The new, rooted cutting will grow into a new vinca.
Select cuttings from the horizontal stems, not the flowering stems. Take cuttings any time of the year, but make sure the cutting is from an actively growing plant. Water the plant well. Do not take cuttings from a wilted plant or during afternoon heat. Secondary cuttings, from lower on the stem, respond better than terminal cuttings at the vinca's tip. New roots usually form in two to four weeks.
Many gardeners set cuttings in water. While this may work for some plants, water will smother the new roots of a vinca cutting. The North Carolina State University Extension recommends using a mix of 80 percent coarse perlite and 20 percent sphagnum peat moss.