Q: I love the look of the periwinkle plant, but my neighbor says it’s invasive. What does that mean exactly? — Lynn Fuccio
A: With beautiful blue flowers, the periwinkle plant certainly creates an alluring effect. Even the name sounds dreamy. But periwinkle may be a bit more mischievous than its easy name suggests. Vinca major and Vinca minor are common versions of the periwinkle plant. Both have similar growth habits and appearance.
Big periwinkle (Vinca major) is a low-growing vining plant. An evergreen perennial, it is quietly showy with oval-shaped, shiny green leaves that grow to 2 to 3 inches in length. Flowers are generally a pretty lilac blue, although there are varietals that have deep purple or white flowers.
Vinca major thrives in moist, rich soil and prefers zones 7 to 9. A sunny to partial shade area will suit it just fine, but a sunny spot will produce more flowers. It is often used as erosion control on a sloping area or as a groundcover in a large spot, but is not recommended for small gardens. Because of its loose growth habit, it is not quite as strong a weed control as other similar groundcovers.
Common periwinkle (Vinca minor) is similar to Vinca major but has smaller leaves and flowers. This varietal tolerates a colder, shadier environment, but handles full sun. It grows in almost any soil, spreading rapidly, especially in rich, moist soil where it quickly becomes invasive. This plant thrives in zones 4 to 9, but appreciates a shadier locale in zones 8 and 9.
According to the California Invasive Plant Council, both Vinca varietals exhibit invasive characteristics. The periwinkle grows rampantly, often with root masses that reach several feet into the ground. This creates a competitive environment with native vegetation — often with the periwinkle ending up the victor. This dominance has a detrimental effect on native habitat and wildlife.
If you are an active gardener, undeterred by the work necessary to keep this plant in check, the periwinkle may be a pretty selection. But be warned, the demure appearance of the periwinkle belies a strong spirit that can become obstreperous before your eyes, taking over your zucchini bed and creeping into that neighbor’s yard. Remember, there is one way to have your plant and contain it too: place this lovely in a nice hanging basket or medium to large planter.
For information on other invasive species refer to the website http://www.plantright.org.