What is it?
This macho Mediterranean creeper is a hard one to get control of once it is established. It was originally planted for its glossy green or variegated green and yellow, or green and white, leaves and striking blue-violet flowers, and unfortunately it is still found in many gardens and along roadsides where it has been dumped or planted.
Why is it wicked?
With stems that can grow to over two metres and take root whereever they come in contact with the soil, periwinkle can make a real mess of bush and wetland areas. It forms dense mats that squash out other groundcovers and stop native plant seedlings establishing, eventually opening the area up to invasion by other weedy species. Being tolerant of semi-shade and full sun, most soils, wet or drought conditions, hot and cold temperatures, heavy damage and grazing, periwinkle tends to be long-lived once it does establish. While it rarely produces seed, it is readily spread through the dumping of garden waste.
What can you do?
Small plants can be dug out, taking care to remove all roots and dispose of plant material at a refuse transfer station. Larger infestations can be sprayed or mowed using a very low setting; both these methods require frequent follow up over two to three years on any regrowth. Otherwise, try weedmatting the infestation for at least six months, making sure no creeping stems escape into the sunlight.
Try speedwell (Veronica prostrata) which has deep green leaves and deep blue flowers, or the striking native creeping fuchsia (Fuchsia procumbens) with its unusual yellow-orange flowers and red berries. Your local DOC office can advise on other natives that grow well in your area.
For more information check out www.weedbusters.org.nz