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Vinca major
Blue Periwinkle
By the end of 2007 Vinca major will be declared a noxious weed in Victoria but it's actually a very serious environmental weed in every State and the ACT. It's also an agricultural weed because it is poisonous to sheep, cattle and horses if eaten.
The plant is a ground-creeping perennial with broadly oval and usually shiny, dark-green leaves that are paler underneath. As it grows it produces long arching stems. As soon as the stem comes into contact with soil, it takes root. This can happen at the stem tip as well as along stem nodes.
In good conditions individual stems can grow by more than a metre in a season. Eventually the plant forms dense low mats that completely smother ground flora and prevents tree and shrub regeneration (as can be seen here).
The flowers are lilac-blue and have five petals that are twisted anticlockwise in bud. The flowers are solitary in leaf axils and appear sporadically and mainly from May to December.
Its ideal environment is damp fertile soils and it really thrives in shaded conditions, although it will tolerate open sunny positions as long as there is plenty of moisture.
Stem and root fragments can be spread easily by water, especially flooding, and it is a plant that is frequently dumped in bushland.
Close Relative
Vinca minor (Lesser Periwinkle) is a particular problem in the Dandenong Ranges in Melbourne's east. It has a similar form but the flowers are white and the foliage is smaller.
Control
Control is very difficult because although this plant produces little or no seed in many cases (in Australia), it has a very tough root system. Young seedlings can be removed by hand and plants that are less than a metre in diameter can be dug out. However, all stems and roots must be removed as it can regenerate from even small fragments of these.
Solarisation (where plastic sheeting is laid over the plant for up to 6 months, then regrowth treated with herbicide) can be effective on small infestations.
Plants larger than a square metre pose a serious control problem because of the tough root system. Plants can be slashed or mown to near ground and the regrowth treated with herbicide, but Vinca major can be quite 'immune' to herbicide. To aid the effectiveness of herbicide, plants should be actively growing and not under heat or water stress. And surfactants in the spray may also improve effectiveness.
Information sources:
Blood, K., 2001, Environmental Weeds - a field guide for SE Australia, CRC Weed Management Systems, published by CH Jerram Science Publishers.
Muyt, A., 2001, Bush Invaders of South-East Australia, published by RG and FJ Richardson.
Click here to return to the invasive plants list.
The information contained on this page is Copyright © SGA and intended for personal use only.
You may not use the information for any other purpose without the express written permission of SGA.