Vinca difformis
intermediate periwinkle
Overview
Vinca difformis is an evergreen, trailing perennial of the dogbane family, forming a loose ground-covering mat of arching and rooting stems 12–36 inches (30–90 cm) long over a clumping crown. The opposite leaves are glossy, lance-shaped to oval, 1.2–3 inches (3–8 cm) long, and remain green through winter in mild climates. Pale blue to lilac-white, five-lobed flowers 1–2 inches (2.5–5 cm) across open from autumn through to spring, with the main flush in late winter, each lobe set at an angle that gives the flower a slightly pinwheel outline. The trailing stems arch outward and root where the tips touch moist soil, slowly widening the colony. The plant grows in sun to part shade on most moist, free-draining soils and tolerates dry shade once established, though it can be cut back by hard frost below about 15°F (-9°C). It is intolerant of waterlogging and prolonged hard freezes, which limit it to mild-winter regions. All parts contain alkaloids that are poisonous if eaten.
Native Range
Vinca difformis is native to the western Mediterranean, including Portugal, Spain, southern France, Italy, and northwest Africa. It grows in scrub, hedge banks, woodland edges, and damp shaded ground.Suggested Uses
Used as evergreen ground cover on banks, in shaded borders, and beneath shrubs and trees where winter flowers are wanted. Suited to mild-climate gardens and large containers that can be sheltered from hard frost.How to Identify
Appearance
Size & Dimensions
Height10" - 1'6"
Width/Spread2' - 5'
Bloom Information
Flowering runs from autumn through spring in mild climates, peaking in late winter from January to March. Individual flowers last several days, and bloom continues over many weeks. In colder areas flowering is later and shorter, beginning only as frost eases.
Detailed Descriptions
Flower Description
pale blue to lilac-whiteFoliage Description
glossy greenGrowing Conditions
Sun Requirements
Requires 3-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in part shade to full sun on moist but free-draining soils of most types. Established plants tolerate dry shade under trees, while staying greener and flowering more in soil that holds some moisture. Hard frost below about 15°F (-9°C) can kill top growth, though plants often regrow from the base. Waterlogged ground causes stem rot. Watering helps during establishment and in summer drought. It suits zones 7 to 9 and is grown as a tender evergreen ground cover in colder areas.Pruning
Stems can be sheared back in early spring to control spread and renew dense growth. Rooted tips are easily separated and replanted. Trimming after the main bloom keeps the mat compact.Container Growing
✓ Suitable for container growing