Vinca minor (common periwinkle) is a perennial groundcover in USDA zones 4 through 9 and an annual plant in colder regions. Although gardeners usually use vinca as a groundcover in shady growing areas, it also makes an attractive trailing plant when you use it in containers. As winter approaches, winterize vinca plants growing in the soil by covering the foliage with a thick layer of mulch. The mulch will prevent harsh winter winds from drying out these perennial plants.
Allow the vinca to continue to grow unprotected throughout the autumn months until late autumn. Vinca will continue to thrive throughout most of the autumn weather, including periodic frosts and freezes.
Apply 3 to 4 inches of shredded mulch over the entire area where vinca is growing in late autumn. One reason for not applying the mulch too early in the autumn season is that it invites rodents to burrow in the mulch and they may spend the winter within the mulch. Spread the mulch evenly over the vinca, covering the foliage completely.
Remove the mulch the next spring when the temperatures begin to moderate. Vinca will tolerate some freezing temperatures, so removing the mulch in early spring is best for the vinca.
Cut back the vinca vines to prune them if they appear overgrown. Most vinca patches will benefit from cutting back to soil level every two to three years. The vinca will regrow with renewed energy after you cut it back.