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Veronica anagallis-aquatica
(Blue Water Speedwell)
Grown as an ornamental plant in garden ponds, this plant is also spreading through our waterways. It is a widespread weed in temperate Australia but it hadn't been seen in Victoria until recently.
Glen Jameson from Parks Victoria contacted SGA in February 2007, advising us that an outbreak of this weed had occurred in the Yarra River in the Westerfolds Park region.
It is spreading at an alarming rate. In spite of being removed from an area a month ago, it has already re-established itself and such is its virulence it has even grown over the top of existing weed species.
Glen is concerned that this outbreak is from a garden or nursery escapee, so SGA nurseries and subscribers are asked to check that this is not a plant they stock or have in their garden ponds. If you have it, please consider the environment.
And if you're out and about in the bush and see this aquatic weed growing, please report it to your local Parks Victoria office. The Cooperative Research Centre (CRC) for Weed Management Systems request that this plant, while not a weed of national significance, not be planted anywhere where escape to waterways is possible.
Description
It's a perennial herb with soft, hollow stems that are quite stout. It grows to about 800mm tall and is fresh green in colour. In spring and summer it produces long racemes of 15 - 40 blue to lilac flowers. The fruit is a circular capsule about 4mm in size.
Control
Aquatic ecosystems are very sensitive, so control of weeds can be quite a problem.
Inappropriate herbicide treatments can have serious environmental consequences. Manual removal or mechanical harvesting is the most preferable control method.
Removal prior to development of the fruit is essential.
Information sources:
Top Image courtesy of David G. Smith, Delaware Wildflowers
Auld, B.A. & Medd, R.W.,1987, Weeds - an illustrated botanical guide to the weeds of Australia, Inkata Press.
CRC Weed Management Systems - weedscrc.katalyst.com.au/bushlandfriendlygardens/listweeds/Q/NSWSoutheast%20Coast.html
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.