Also known as common periwinkle (and thus where the color of the same name comes from), this sub-shrub is native to central-southern Europe and was brought to the United States as an ornamental ground cover. It is an evergreen ground cover that is rarely seen over 6 inches in height, but spreads widely through runners that will root upon contact with the ground. The leaves are small (1.5 inch long) and glossy with a leathery texture. The flowers are a violet-purple (periwinkle) roughly an inch in both length and diameter with 5 attached petals.
Very tolerant of many different soil types, including poor conditions, the greatest limiting factor to growth of Myrtle is moisture. In addition to a relatively high tolerance of poor conditions, Myrtle spreads widely across open areas. This leads to the crowding-out and smothering of other sub-shrubs in the area, leading to the invasive title. Mechanical and chemical weeding can be used to control growth/eliminate stands of the plant. Due to the extensive root base from any point of stem contact, it is necessary to make sure all the roots have been dug up or a proper herbicide has been used.