The plant commonly referred to as periwinkle is often confused, as the name applies to two different species. The hardy, perennial groundcover is an evergreen vine belonging to the genus Vinca (Vinca minor or Vinca major). This article focuses exclusively on cultivating the robust Vinca species, known for quickly covering large areas with glossy foliage. The other plant, Catharanthus roseus (Madagascar periwinkle), is an upright, tender annual requiring full sun and different care.
Selecting the Site and Soil Preparation
Establishing a successful periwinkle patch begins with proper site selection. While Vinca tolerates a wide range of light conditions, it thrives best in partial to full shade, which helps preserve the rich color of its evergreen leaves. Full sun exposure is tolerated only if the soil remains consistently moist; otherwise, the foliage may scorch.
The ideal soil is moist, well-draining, and rich in organic matter. Although periwinkle is adaptable and can survive in poor, clay, or sandy soils, growth is denser and more vigorous in fertile conditions. Before planting, amend the area by incorporating aged compost or well-rotted manure into the top six to eight inches of soil. This preparation improves drainage, preventing root rot, and aids moisture retention, which is crucial for young plants.
Periwinkle tolerates a slightly acidic to neutral soil pH, common in woodland settings where it naturally thrives. Spacing Vinca minor plants approximately 12 to 18 inches apart allows the creeping stems to quickly intertwine and create a uniform, dense mat. Proper preparation ensures the plant establishes deep, healthy roots.
Watering, Feeding, and Routine Maintenance
Initial watering is critical for new periwinkle plantings to encourage deep root establishment. Newly installed plants should be watered deeply and regularly, typically once a week or whenever the top few inches of soil feel dry. Consistent moisture during the first growing season is necessary for the vining stems to root effectively at the nodes.
Once established, periwinkle’s watering needs decrease significantly, making it drought-tolerant. Mature plantings usually thrive on natural rainfall but benefit from deep supplemental watering during extended dry periods. Overwatering should be avoided, as Vinca is susceptible to fungal issues like root rot if the soil becomes waterlogged.
Periwinkle is a light feeder and generally requires minimal fertilization, especially when planted in organically rich soil. If the foliage appears pale or growth is sparse, a single annual application of a balanced, slow-release fertilizer in early spring can provide a boost. Alternatively, top-dressing the area with a thin layer of compost supplies nutrients and improves soil structure without the risk of promoting leggy growth.
Routine maintenance primarily involves managing the plant’s height and density. To rejuvenate a patchy or overgrown area, periwinkle can be sheared or mowed high in early spring before new growth begins. Cutting the entire patch back to about four to six inches promotes a flush of dense, healthy foliage and controls the overall height.
Managing Aggressive Growth
The vigorous, rooting nature that makes periwinkle an effective groundcover also means it can become aggressive if left unchecked. The plant spreads by sending out long, trailing stems that root wherever they touch the soil, creating a thick, clonal colony. To prevent the plant from invading adjacent garden beds, physical containment is the most reliable method.
Installing a metal or plastic edging barrier, buried six to twelve inches deep, can effectively block the spread of the creeping runners. Sidewalks, driveways, and building foundations also act as natural barriers to contain the plant’s horizontal expansion. Regular pruning or trimming the runners along the borders helps keep the planting neat and prevents encroachment.
For removal in problem areas, manual extraction is necessary and requires thoroughness. Since even small stem fragments can re-root, all parts of the vine and its extensive root system must be dug out completely. In large, severely overgrown areas, a systemic, oil-based herbicide may be needed, as the leaves’ waxy coating resists water-based applications, but this should be used with caution.