Family: Apocyanaceae

Status:

Description:
A spreading groundcover, which form extensive mats, but does not climb. Broad-oval, hairless, glossy dark green leaves, about 5cm long and in opposite pairs. There are cultivars with variegated foliage, which are also weedy. Flowers are mauve to purple, with a distinctive twist in the petals.

Preferred habitat and impacts:
Moist shady situations will produce thickest growth. Commonly occurring along river banks, on silty alluvial soils, but may also appear around the edges of towns, in cemeteries and anywhere where garden refuse is dumped.

Forms dense mats which smother all native groundcover vegetation and prevent regeneration of trees and shrubs. This can have important long term consequences on streambanks, where the eventual loss of native tree and shrub cover could lead to erosion.

Dispersal:
Does not usually produce seed in Australia. Broken off sections of stem will take root, and existing plants spread by rooting at the nodes. Spread down rivers by floods, and into other areas by dumping of garden waste.

Look-alikes:
Periwinkle is quite distinctive, although non-flowering small plants could be mistaken for the small native vine Tylophora barbata. However, Tylophora twines up nearby plants, while periwinkle seldom climbs.

Control:
Very small infestations can be dug out, but every fragment of stem can potentially re-grow and needs to be removed and destroyed off-site. In sunny situations, covering the plant with plastic sheeting for 4-6 months in the warmer months will weaken the plant. After removing the plastic any regrowth can be dug or sprayed. This method will not work in the shade. Spraying with selective or non-selective herbicides will work eventually, but repeat treatments of regrowth will be needed. Plants should not be under any moisture stress when sprayed. Surfactants will improve penetration into the waxy-coated leaves.

If treating riverbank infestations, it will be necessary to plant native vegetation after treatment, to prevent erosion. Consult with the Department of Land and Water Conservation before commencing any removal of vegetation on river banks. Remember that there are restrictions on the use of herbicides in watercourses.