bigleaf periwinkle

Vinca major

Bigleaf periwinkle, Vinca major, a dicot, is a perennial herb that is not native to California; it was introduced from elsewhere and naturalized in the wild. It’s bloom period is January-May.

Etymology   Description   Distribution and habitat   Subspecies   Cultivation   Gallery   Invasive plant species

additional informational links: Wikipedia , Calflora 

click image for maximum resolution