Blue heliotrope (Heliotropium amplexicaule) is a native plant of South America. Its cousin, common heliotrope (Heliotropium europaeum L.) is from southern and central Europe, western Asia and northern Africa. Both species can be very toxic to animals. Blue heliotrope is the more common of the two found in north-west NSW.
Both plants readily establish along roadsides, (see photo, right), disturbed areas, fallows and degraded pastures. The plants are spread by seeds and rootstocks. The root system is complex and can go some metres in depth – one of the reasons why the plant is so hardy, and difficult to control.
How to identify blue heliotrope
Blue heliotrope flowers vary from purple to lilac – even white in some cases. Common heliotrope has white flowers. Both species produce yellow centres. A reliable guide to identification is the characteristic bend
in that main part of the plant that holds the flowers – as indicated in the photos, left and right. Both blue and common heliotrope emit very strong and unpleasant odours during their main growing and flowering periods.
Effect on animals?
Blue heliotrope is poisonous to cattle, especially young cattle. According to Noxious Plants of Australia by Parsons and Cuthbertson (Inkata Press), blue heliotrope causes acute and chronic liver damage:
“Symptoms of poisoning include depression, photosensitisation, scouring, straining, abdominal swelling, depraved appetite, staggering gait, circling and death. Autopsy reveals enlarged, hardened and sometimes nodulated livers with enlarged thick-walled gall bladders. There is a massive build-up in the abdomen and, while the rumen is distended with ingesta, virtually empty intestines.”
The editor has also been told of cases where cattle that were moved straight from a paddock containing blue heliotrope to a feed lot have died after consuming the new, high-protein food. Their systems couldn’t handle the sudden change in diet… LRT May 09.
Common heliotrope is toxic to sheep, cattle and horses, especially when the animals are subjected to repeated grazing on this plant and other plants with similar qualities (such as Paterson’s curse).
As with all problem plants the risk to animals is higher when they are put into a new paddock. In these situations, stressed and disorientated animals will often try a variety of plants that they would not normally eat.
Biological: NSW DPI’s Weed Biological Control Unit in collaboration with CSIRO Canberra released (2001) a biological agent for control of blue heliotrope. In north-west NSW, Deuterocampta quadrijuga leaf feeding beetles were released on Upper Horton properties “Kildare” and “Trevallyn” 7 Jan 2003. Subsequent releases were made at various sites including the Gwydir and Dumaresq Rivers. The Gwydir River site near Bingara has been the only real success story so far in this part of NSW: it continues to maintain its beetle population (as at 2017). Every summer hundreds of beetles have been collected from this particular site. The beetles have had a definite impact on plant density at this site. And, they are still slowly spreading to adjacent areas.
The CSIRO also trialled a second agent, a Longitarsus species “flea beetle“. I have no current information on this project.
The use of biocontrol comes with an important proviso!
These insects may well play a very important, future role in providing a level of control in large areas of blue heliotrope or in situations such as river systems where herbicide is beyond practicality. BUT, if you only have a small area of blue heliotrope, or an area of blue heliotrope that can be accessed easily with a spray unit, please DON’T just leave it to the beetles. Concentrate on wiping out any new infestations through a systematic herbicide spray program…
Non-Chemical Options: Dig out single plants. Improve pastures with vigorous perennial species.
Ploughing is not an option because it breaks up the plant and root pieces and (b) dormant seeds will be brought to life. Chemical Options:
|Triclopyr 300 g/L + picloram 100 g/L eg Grazon DS®||500 ml per 100 L water||Apply at flowering in a minimum spray volume of 1250 L/Ha.|
|Dicamba 500 g/L eg Kamba M®||130 mL per 15 L water 600 mL per 100 L water 8.8 L per hectare||Knapsack spray. High volume spot spray. Boom spray. Apply to young, actively growing plants|
|2,4-D 300 g/L + picloram 75 g/L eg Tordon® 75-D||1.0 L per 100L water||Grass pastures only. Spot spray. Apply to young, actively growing plants.|
|Fluroxypyr 200 g/L eg Starane®||1.0 L per 100 L water||Spot spray. Apply during flowering.|
|Tebuthiuron 200 g/L eg Graslan®||0.5 g per square metre||DO NOT use within 30 m of trees, DO NOT apply to areas greater than 0.5 hectares in size|
|Metsulfuron methyl 600 g/L Various trade names eg Brushoff®||10 g per 100 L of water||Plus 1.0% surfactant. Spot spray. Apply when plants are actively growing spring to autumn. See APVMA Permit PER12286 (in force from 4 Oct 2010 to 3 Oct 2015)|
|Glyphosate 360 g/L Glyphosate 450g/L Various names||1.0 L per 100 L water 0.8 L per 100 L water||High volume spot spray. Spray when plants are actively growing from late spring to autumn – before seed set. DO NOT apply to stressed plants. For more information refer to APVMA permit PER11738 (in force from 19 Oct 209 to 31 Oct 2013). EXPIRED|
IMPORTANT: USE OF PESTICIDES – ALWAYS READ THE LABEL
Pesticides must only be used for the purpose for which they are registered and must not be used in any other situation or in any manner contrary to the directions on the label. Never use a herbicide in any way contrary to the label recommendations.
MORE INFORMATION: “Noxious Plants of Australia”, by Parsons and Cuthbertson [Inkata Press].
DISCLAIMER: The information contained in this web site is based on knowledge and understanding at the time of writing. However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of North West Weeds or the user’s independent adviser. Les Tanner 16/12/16