Quick Facts

Quick facts

• Although only found near Eden in southern New South Wales, Blue Hound's Tongue (Cynoglossum creticum) is a threat to agriculture in southern Australia.
• The closely related weed Hound's Tongue (Cynoglossum officinale) is a major weed of pastures in North America.
• It is toxic to stock and invades grasslands, suppressing native grasses.
• Prevention and early intervention are the most cost-effective forms of weed control.
• If you see a plant that may be Blue Hound's Tongue, contact your local council or state or territory weed management agency. Do not attempt control on your own.

What Does It Look Like?

What is it?

Blue Hound's Tongue (Cynoglossum creticum) is a biennial herb that grows up to 600 mm high. Its stems are densely covered with fine hairs. It has long, narrow dark-green leaves, up to 200 mm long and up to 35 mm wide, covered with long, coarse hairs. The base of the leaf is heart-shaped and clasps the stem. The leaves occur alternately along the stem and decrease in size up the stem. Blue Hound's Tongue has a long taproot which is used to store energy reserves. In the first year of growth, Blue Hound's Tongue forms a rosette; this is followed by one or more tall flowering stems during the second growing season.

The flowers, up to 9 mm in diameter, consist of five, hairy, green sepals and five small petals. The petals range in colour from pink to blue and have obvious darker-coloured veins marking them. Five dark stamens occur at the base of the flower tube.

Each flower produces four seeds, known as 'burrs', which when mature, are covered with numerous short, hooked or barbed prickles (Kovander 1972; Wilson 1992; CRC 2003).

For further information and assistance with identification of Blue Hound's Tongue contact the herbarium in your state or territory.

Flower colour

Blue

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

In its native region, blue hound's tongue is found in mediterranean / warm temperate grassland and open woodland communities, at altitudes from sea level to 1000 m. It favours open, usually dry habitats (Kovander 1972) and is well suited to disturbed sites such as roadsides and sand dunes (CRC 2003). In Australia, it has been recorded growing in pasture and other weed dominated vegetation near Eden in New South Wales. In North America, the closely related Hound's Tongue (Cynoglossum officinale) is successful as a weed in habitats disturbed by logging, grazing and other activities (CRC 2003).

Are there similar species?

Several Australian native herbs have similar hooked burrs and are similar in appearance to Blue Hound's Tongue. These include Forest Hound's Tongue (Austrocynoglossum latifolium), Australian Hound's Tongue (Cynoglossum australe) and Sweet Hound's Tongue (Cynoglossum suaveolens) (Richardson et al. 2006).

Forest Hound's Tongue has trailing, as opposed to erect stems, broader leaves (up to 6 cm wide) and white flowers. Australian Hound's Tongue differs from Blue Hound's Tongue by having smaller light blue to white coloured flowers and by having burrs with a flattened rim. Sweet Hound's Tongue differs from Blue Hound's Tongue by its small leaf like bracts at the base of each flower and usually white flowers, although occasionally it may also have blue flowers.

Why Is It A Weed?

What are its impacts?

Blue Hound's Tongue is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia's ecosystems (CRC 2003).

Agriculture: Blue Hound's Tongue contains pyrrolizidine alkaloids that can be toxic to livestock. Poisoning may occur when stock are fed hay or chopped forage containing the plant. It has the potential to become troublesome in Australian pastures and grasslands by competing with established communities and hindering regeneration and establishment (Richardson et al. 2006; CRC 2003). The burrs of Blue Hound's Tongue can attach to livestock and may cause irritation and taint wool (CRC 2003).

Native ecosystems: The severe impacts recorded overseas by the related species, Hound's Tongue (Cynoglossum officinale), suggest that Blue Hound's Tongue could become a major problem in Australia. In Canada, Hound's Tongue has become a major economic problem, with logged forests providing an ideal habitat for seedling establishment. Other factors, such as seed dispersal by livestock, a favourable climate and a topography that hinders mechanical and chemical control, have helped the plant spread from a few sparsely scattered weeds in the 1960s to a current infestation of 2000 ha (CRC 2003).

Another closely related species, Cynoglossum coeruleum, is also considered a weed and its importation into Australia is banned by the Australian Quarantine and Inspection Service (CRC 2003).

How does it spread?

Blue Hound's Tongue spreads by seeds, with mature plants each producing several hundred (CRC 2003). The seeds are covered in minute hooks that allow them to attach to the clothing of people and to the hair of animals allowing them to spread over long distances (CRC 2003). Because most seeds germinate soon after formation and seed viability is only 2–3 years, there is little development of a soil seedbank (CRC 2003). Seedlings are fast growing. In North America, cattle and wildlife are important vectors in the spread of the closely related hound's tongue (Cynoglissum officinale) (CRC 2003).

What is its history in Australia?

The earliest known record of Blue Hound's Tongue in Australia is an herbarium specimen, presumably of a cultivated plant, collected from the Royal Botanic Gardens in Sydney in 1898. Herbarium records held by the National Herbarium of New South Wales suggest that it was first recorded as naturalised in Australia in 1933, growing in a weed infested slope near Eden. Other records held by the National Herbarium of New South Wales confirmed this population as being present at least until 1976. Two new infestations (10 km to the west of Eden, along the Towamba River) were recorded in 2004. At these sites, there are several hundred plants covering about 0.5 ha, with other plants scattered over an area of 20–30 ha. The upstream location of these new outbreaks indicates that seed is likely to have been transported there by animals or human activity (CRC 2003).

How To Manage It?

Best practice management

Early detection and eradication are crucial. Small infestations can be eradicated if caught early enough. It is highly recommended that any new outbreaks should be reported immediately to your state or territory weed management agency or local council. Do not try to control Blue Hound's Tongue without their expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem (CRC 2003).

Non-chemical control: Crop management: Maintaining a competitive pasture will help reduce the opportunities for undesirable plants to invade. Paddocks infested with Blue Hound's Tongue should not be used for livestock during and after flowering in order to prevent the spread of seed. Additionally, where cattle come in contact with Blue Hound's Tongue, they must be thoroughly inspected and cleaned before being transported or moved to new areas (CRC 2003).

Once the initial infestations are controlled, follow-up monitoring and control will be required to ensure that reinfestation does not occur.

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au .

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Blue Hound's Tongue has a biennial life cycle that is completed in two years or seasons, with the second season usually devoted to flowering and fruiting. Seeds generally germinate during the autumn months. Seedlings form a rosette during autumn and winter and finally flower during spring and summer. The stimulus for flowering is a combination of summer moisture, rosette size and vernalisation (exposure to a period of low temperatures). The rosettes may not flower, but pass the winter to flower in the following year. The plant dies after flowering, but seeds may stay attached until the following spring, delaying germination for a year (CRC 2003).

Where Is It Found?

Which states and territories is it found?

NSW

What areas within states and territories is it found?

Blue Hound's Tongue is currently only recorded near Eden, New South Wales (CRC 2003; Richardson 2006; Wilson 1992). It is also recorded as a weed in Argentina and Chile (Holm et al. 1979).

Where does it originate?

Blue Hound's Tongue is a native of southern Europe (Kovander 1972; Wilson 1992; CRC 2003) and northern Africa (African Flowering Plants Database 2007).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

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

Cynoglossum creticum

Other scientific names (synonyms)?

Cynoglossum pictum Sol. ex Aiton