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Blue hound’s-tongue (Cynoglossum creticum)

Blue Hound’s-tongue is a toxic introduced weed recorded near Eden in New South Wales, where it can invade pasture and grassland. It can compete with established vegetation, hinder regeneration and produce burrs that attach to livestock and may irritate animals or taint wool.

Key facts

Type: Weed, herb.

Native to: Southern Europe and northern Africa.

Established in: NSW, VIC.

Other names: Cynoglossum pictum.

Best time to act: Look for seedlings and rosettes in autumn and winter and flowering plants in spring and summer, and report infestations early.

Identification

  • A biennial herb, it grows up to 600 mm high and has stems densely covered with fine hairs.
  • Its long, narrow, dark-green leaves have coarse hairs, clasp the stem at a heart-shaped base and become smaller further up the stem.
  • In its first year it forms a rosette; in the second growing season it produces one or more tall flowering stems.
  • Flowers are up to 9 mm across, with pink to blue petals marked by darker veins.
  • Each flower produces four burrs, which mature with numerous short, hooked or barbed prickles.
  • Look-alike: Forest Hound’s Tongue (*Austrocynoglossum latifolium*) has trailing stems, broader leaves and white flowers; Australian Hound’s Tongue (*Cynoglossum australe*) has smaller light-blue to white flowers and burrs with a flattened rim.
  • Look-alike: Sweet Hound’s Tongue (*Cynoglossum suaveolens*) has small leaf-like bracts at the base of each flower and usually white flowers, though these can occasionally be blue.

Where it grows

In Australia, it has been recorded in pasture and other weed-dominated vegetation near Eden in New South Wales.

Why it matters

  • It contains pyrrolizidine alkaloids that can poison livestock, including when they eat hay or chopped forage containing the plant.
  • It can compete with established pasture and grassland communities and hinder regeneration and establishment.
  • Its burrs can attach to livestock, causing irritation and potentially tainting wool.
  • It is on the Alert List for Environmental Weeds because it has the potential to seriously degrade ecosystems.

How it spreads

  • Mature plants produce several hundred seeds, and the seeds’ minute hooks can attach to people’s clothing and animals’ hair, carrying them over long distances.
  • Most seeds germinate soon after forming, and seed viability is only 2–3 years, so little soil seedbank develops.
  • In North America, cattle and wildlife spread the closely related Hound’s Tongue (*Cynoglossum officinale*).

Control options

  • Report suspected plants or new outbreaks promptly to the state or territory weed management agency or local council, and do not attempt control without their expert assistance.
  • Maintain competitive pasture to reduce opportunities for the weed to invade.
  • Keep livestock out of infested paddocks during and after flowering to help prevent seed spread.
  • After initial control, monitor and follow up to check for reinfestation.

Hygiene and washdown

  • The hooked burrs can cling to clothing, so check and clean clothing after contact with plants.
  • Thoroughly inspect and clean cattle that have contacted the weed before transporting or moving them to new areas.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria

Sources