Family: Apocynaceae

Origin, Description & Uses:
Vinca minor, commonly known as common periwinkle, small periwinkle, or running-myrtle, is a low-growing perennial ground cover native to southern Europe. It forms dense mats of trailing stems with glossy, dark green, opposite leaves and produces attractive five-petaled, violet-blue flowers in spring and, in favorable conditions, intermittently throughout the year. Numerous ornamental cultivars are available, including forms with white or double flowers and variegated foliage. Because of its ability to spread and stabilize soil, V. minor is widely planted as an ornamental ground cover for shaded landscapes, erosion control, and difficult planting sites. In Hawaiʻi, it has been cultivated primarily in cooler, higher elevation gardens.

Risks & Threats:
Although Vinca minor is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that are cause for concern. It spreads readily by creeping stems that root at the nodes, allowing it to form dense, persistent mats that can suppress the growth and regeneration of other plants. In regions where it has escaped cultivation, it has invaded forests, woodlands, and other natural habitats, displacing native vegetation and reducing plant diversity. Its tolerance of shade, ability to survive in a range of soil conditions, and vegetative persistence increase its potential to spread beyond intended planting areas. Because these characteristics could detrimentally impact tropical island ecosystems if the species were to escape cultivation, Plant Pono recommends choosing a low-risk or native ground cover alternative whenever suitable options are available.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Widely naturalized (not documented in the Hawaiian Islands)
  
• Garden and environmental weed
  
• Vinca major is also invasive
  
• Relatively unpalatable to browsing and grazing animals
  
• Toxic to animals and potentially toxic, and allergenic to humans
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Forms thick mats that smother the ground and low-growing vegetation
  
• Reproduces rapidly by vegetative means
  
• Vegetative fragments spread in garden waste, and by water
  
• Able to resprout after cutting

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Ornamental and medicinal uses
  
• Rarely, if ever, produces seeds in introduced range
  
• Lack of seed production may limit ability to disperse and spread
  
• Certain herbicides may provide effective control