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Periwinkle flower. -
Large periwinkle flower. Photo Credit: Barry Rice, sarracenia.com, Bugwood.org -
Large periwinkle infestation. Photo Credit: Nancy Loewenstein, Auburn University, Bugwood.org -
Small periwinkle leaves. Photo Credit: Chris Evans, University of Illinois, Bugwood.org -
Small periwinkle. Photo Credit: Chris Evans, University of Illinois, Bugwood.org
Also known as:
- Small periwinkle: common periwinkle, myrtle, creeping myrtle
- Large periwinkle: big periwinkle, bigleaf periwinkle
Both large and small periwinkle are trailing, evergreen perennials. They produce eye-catching purple-blue flowers leading to them being the highlight of local gardens. Once outside garden beds, they can become a nuisance in forests, forming extensive mats that don’t allow other plants to grow.
Description:
| Life Cycle: | Perennial (life cycle lasts more than one year) |
| Early Detection and Rapid Response species: | No |
| Height: | Small periwinkle: Can grow up to 15 inches high (40 centimeters) Large periwinkle : Can grow up to 35 inches high (90 centimeters) |
| Leaf Description: | Both species produce glossy, dark green leaves that have a leathery texture. Both species leaves are evergreen. Small periwinkle’s leaves are smaller and lance-shaped whereas large periwinkle’s leaves are broader and somewhat heart-shaped. |
| Fruit & Flower Description: | Flowers are solitary, meaning a single flower grows at the end of single stem. Flowers are a showy purple-blue and have five pinwheel-like petals. Small periwinkle’s flowers are approximately half the size of large periwinkle’s flowers. |
| Bloom Time: | Early spring through fall |
Habitat:
- Both species are frequently found in shaded forests, gardens, and along roadsides.
- They thrive in areas with well-drained, moist soils and partial sun. But they can grow in full shade and poor soils.
Impact:
- Once established, both species develop into a dense ground cover that outcompetes other vegetation in natural areas.
- They spread from trailing stems and root fragments. This allows them to spread outside gardens if not properly cared for.
What you can do about it:
- Both periwinkle species are often planted in gardens as an ornamental groundcover. If you are planning on including them in your garden, make sure to keep them pruned to stop them from spreading into natural areas.
- In natural areas, hand pulling can be effective. Pay careful attention to removing all stems and roots. They are deep-rooted so extra effort may be needed to dig them out.
- Whenever removing or pruning either species, put all the plant material in a plastic bag and dispose of it in the trash – not the yard debris.
- Because these species can resprout from stem fragments, mowing is not a recommended control method.
Look-alikes:
Old man’s beard (Clematis vitalba) and both periwinkle species have similar waxy, evergreen foliage and viny stems. Old man’s beard flowers are cream colored, and often grow in loose clusters.
Noxious Weed Listing:
| State of Oregon: | Not Listed |
| State of Washington: | Not Listed |
More Resources:
Download the Large and Small Periwinkle Best Management Practices Factsheet
- University of California, Weed Research & Information Center: Big periwinkle