On Saturday, December 6, a dedicated crew set out to vanquish what we thought was a small infestation of Vinca major (Big Periwinkle) next to the Cobal Canyon Trail.
Big Periwinkle is native to central Europe and the Mediterranean region. It was introduced to the United States in the 1700s as an ornamental and for medicinal uses. With its dark glossy green leaves and showy purple flowers, Big Periwinkle has become a popular ornamental ground cover, but when plants escape to the wild and find favorable conditions, they can spread invasively, forming a dense ground cover that outcompetes native vegetation. It grows best in moist, shady conditions, such as riparian corridors. Such infestations along streams can easily spread, as small pieces of stem can break off, float downstream, and sprout roots when they land to start a new infestation.
On Saturday, the volunteers set to work, but as we tackled the infestation, we realized it went farther upstream than we had known, as it couldn’t be seen from the trail. It became clear that the upstream plants were older and much more massive root systems than the plants at the downstream end.
Nonetheless, we removed all the Periwinkle from the originally targeted areas and some of the more upstream infestation. Here are some before and after photos:
Many thanks to all the hard-working volunteers! Stay tuned for another workday to tackle the rest of the Periwinkle!
Friends of the Claremont Hills Wilderness Park 