Quick Facts

Quick facts

• Blue Heliotrope (Heliotropium amplexicaule) is a spreading to prostrate herb that grows to a maximum height of 60 cm and has blue flowers with a yellow centre.
• Over the last 40 years, Blue Heliotrope has rapidly expanded its distribution and is now found over large areas of south-eastern Queensland and northern New South Wales.
• Biological control of this species shows promise, with one insect already released and another undergoing testing.
• Blue Heliotrope is very drought tolerant and responds rapidly to increases in rainfall, thus out-competing any regenerating desirable crop and pasture species.
• Blue Heliotrope contains chemicals that are toxic to livestock; accumulations of the toxins may result in the decline of animal performance or even the death of livestock.

What Does It Look Like?

What is it?

Blue Heliotrope (Heliotropium amplexicaule) is a perennial, spreading to prostrate herb that grows to a maximum height of 60 cm. When mature, the plant has a very stout, woody rootstock. The stems are covered by a mix of glandular and non-glandular hairs. The leaves are arranged alternately along the stems, are dull green in colour and soft to touch due to a covering of hairs. Each leaf is up to 90 mm long, up to 25 mm wide and is either not, or only very shortly stalked (Parsons & Cuthbertson 2001; Navie 2004).

The flowers are small, tubular (up to 6 mm diameter), mauve to blue in colour with a yellow centre, and are arranged along one side of a coiled flower spike.

The spikes uncoil as the fruit inside the flowers mature. The fruit consists of two dark-brown, wrinkled nutlets (Parsons & Cuthbertson 2001; Navie 2004).

For further information and assistance with identification of Blue Heliotrope contact the herbarium in your state or territory.

Flower colour

Blue, Purple

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Blue Heliotrope is a weed of warm temperate, subtropical and sometimes also semi arid regions of Australia. It has been recorded growing on many different soil types (Craven 1996), invading pastures, crops and fallows, roadsides, turf, disturbed sites and waste places (Craven 1996; Navie 2004). The major infestations in New South Wales occur in areas that receive more than 500 mm of rainfall per year, although it is also established areas that receive less (Dellow et al. 2004).

Are there similar species?

Blue Heliotrope (Heliotropium amplexicaule) is distinguished from other native and non-native Heliotropium species that occur in Australia by the presence of glandular hairs in the stems and leaves, the attenuate base of the leaf blade (i.e. tapering to a narrow point at the base of the leaf), and especially by the two hairless nutlets (Craven 1996).

Blue Heliotrope may also be confused with some of the low-growing Verbena species, which have similar tubular flowers. Veined Verbena (Verbena rigida) can be differentiated from Blue Heliotrope by its coarse-textured and serrated leaves, while Mayne's Pest Glandularia aristigera [as Verbena aristigera] has highly divided leaves. Also, neither of these species has the coiled inflorescence present in Blue Heliotrope (Navie 2004).

Why Is It A Weed?

What are its impacts?

Agriculture: Blue Heliotrope can compete successfully with desirable crop and pasture species (Parsons & Cuthbertson 2001; Zapater et al. 2004). It has shown a remarkable ability to recover and spread after periods of drought (Dellow et al. 2004; NSW DPI 2007), when it very quickly out-competes desirable species for both moisture and nutrients (NSW DPI 2007). It is recognised as a problem species in sugar cane crops in Queensland (Parsons & Cuthbertson 2001).

Blue Heliotrope contains pyrrolizidine alkaloids that are toxic to livestock; accumulations of these alkaloids may cause a decline in animal performance and may even result in death of livestock (Glover & Ketterer 1987).

How does it spread?

Blue Heliotrope reproduces by seed and root fragments. Seed may be spread by water, especially where plants grow in riparian habitats and on steep terrain where erosion and runoff occurs. Contaminated soil, fodder, vehicles and the fur and manure of livestock are also vectors for transport of Blue Heliotrope seed in Australia (Parsons & Cuthbertson 2001). It is readily dispersed along roadsides during roadside maintenance (Parsons & Cuthbertson 2001). Regeneration of Blue Heliotrope from root fragments occurs readily, especially after mechanical disturbance such as cultivation and hand pulling (Parsons & Cuthbertson 2001).

What is its history in Australia?

It is thought that Blue Heliotrope was introduced into Australia as a garden plant (Craven 1996). It was first recorded in Australia from Athelstone, South Australia, in 1893 from South Brisbane, Queensland, in 1902 (Craven 1996) and in the Hunter Valley, New South Wales, in 1908 (Dellow et al. 2004).

How To Manage It?

Best practice management

Chemical control: Application of herbicide to Blue Heliotrope can provide effective control (Parsons & Cuthbertson 2001). However, the chemicals currently registered for Blue Heliotrope have had limited success and are not selective (Briese et al. 2000; Briese & Zapater 2001; Zapater et al. 2004, CSIRO Entomology 2007). Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au .

Non-chemical control: Effective control of seedlings in spring and summer can be achieved by cultivation (Parsons & Cuthbertson 2001), although this may stimulate germination of dormant seeds, spread root fragments of mature plants and encourage regeneration from the rootstocks of harvested plants (Parsons & Cuthbertson 2001).

A combination of control techniques including mechanical cultivation, herbicide application and good pasture management are necessary to manage Blue Heliotrope on arable land (Dellow et al. 2004).

Biological control: Blue Heliotrope has also been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. A biological control project for Blue Heliotrope in Australia began in 1998 with the search for potential natural enemies (Briese et al. 2000, Briese & Zapater 2001, Zapater et al. 2004). The leaf-beetle (Deuterocampta quadrijuga) was approved for release as a biological control agent of Blue Heliotrope in July 2001 (Briese & Zapater 2001).

In addition, the Flea Beetle (Longitarsus sp.) has shown potential as being a useful control agent against Blue Heliotrope in Australia (Zapater et al. 2004).

Does it have a biological control agent?

YES

When does it grow? (lifecycle/growth calendar)

Seeds of Blue Heliotrope germinate throughout summer, with a major flush occurring in late summer or autumn if sufficient moisture is available (Parsons & Cuthbertson 2001). Several long, prostrate stems develop from a central rosette. Flowering stems grow from these lateral stems and flowering begins in late spring and continues until early autumn (Craven 1996; Parsons & Cuthbertson 2001). During winter in the colder regions, vegetative growth virtually ceases until the temperature increases in spring. Some growth, albeit slow, may occur during winter, especially in warmer areas (Parsons & Cuthbertson 2001). Established plants produce a flush of new growth and begin to flower in spring and autumn (Parsons & Cuthbertson 2001). In warmer areas plants may flower and set seed as early as July (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

NSW, NT, QLD, SA, VIC

What areas within states and territories is it found?

Blue Heliotrope is a widespread weed in south-eastern Queensland and northern New South Wales, but is also present in other parts of New South Wales and Queensland (Parsons & Cuthbertson 2001). In New South Wales alone it infests over 110 000 ha (Da Silva 1991). It is also naturalised in south-eastern South Australia near Adelaide, in the Flinders Ranges and at Melrose and Victor Harbour (Parsons & Cuthbertson 2001). It has also been recorded from northern Victoria (Navie 2004) and the Northern Territory (AVH 2007). It has not been recorded from Western Australia or Tasmania.

Blue Heliotrope is also naturalised in Africa (African Plants Database 2007), the United States (USDA 2007) and Europe (Brummitt 1972).

Where does it originate?

Blue Heliotrope is native to South America, where it is found in northern and central Argentina, southern Bolivia, Uruguay and the extreme south of Brazil (Johnston 1928).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Heliotropium amplexicaule

Other scientific names (synonyms)?

• Cochranea anchusaefolia Gurke (incorrect spelling)
• Cochranea anchusifolia (Poir.) Gurke
• Heliotropium anchusaefolium Poir. (incorrect spelling)
• Heliotropium anchusifolium Poir.
• Tournefortia heliotropoides Hook.

Does it have other known common name(s)?

Wild Heliotrope, Clasping Heliotrope, Creeping Heliotrope, Heliotrope, Purpletop, Turnsole, Wild Verbena