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Hawthorn (Crataegus monogyna)

Hawthorn was introduced to Australia as an ornamental and hedge plant and is now widespread in cooler parts of south-eastern Australia. It forms dense, thorny thickets that can displace native plants, restrict access for larger fauna and reduce stock grazing.

Key facts

Type: Weed, tree.

Native to: Western Europe, the Mediterranean region, Asia Minor and Afghanistan.

Established in: NSW, ACT, VIC, TAS, SA.

Other names: Singleseed Hawthorn, English Hawthorn, May Hawthorn, Whitethorn.

Identification

  • A dense, low-branched deciduous tree or tall shrub, usually 2 to 6 metres tall.
  • Its stems have stout woody thorns about 0.5 to 2.5 centimetres long.
  • The alternate, leathery leaves are lobed, usually with 3 to 7 lobes and toothed edges.
  • White, cream or pink flowers grow in dense clusters, mainly in spring.
  • Fleshy red to deep-red fruits ripen in summer and usually contain one hard brown seed.
  • Look-alike: Azzarola (Crataegus x sinaica) has larger fruits, usually with 2 to 3 large seeds, and young stems covered in soft hairs.
  • Look-alike: Cotoneasters have leaves with entire margins and no spines, while Firethorns have leaves that are not lobed.

Where it grows

In Australia, Hawthorn occurs in the ACT, New South Wales, Queensland, South Australia, Tasmania and Victoria, particularly in cooler, wetter districts and along roadsides, forest margins, waterways, grasslands, open woodlands and poorly managed pastures.

Why it matters

  • Dense patches can displace native plants, shade native flora and inhibit the growth and regeneration of overstorey plants.
  • Thickets can restrict the movement of larger fauna and reduce available habitat, and may provide cover for rabbits.
  • Dense stands can reduce stock grazing capacity, while the plant may also host pests and act as a reservoir for fire blight bacterium affecting apples and pears.

How it spreads

  • Birds and mammals, including foxes, possums and wallaroos, eat the red fruits and disperse the seeds; seeds can also be moved by water.
  • Hawthorn can produce suckers after disturbance, although this is not common.
  • Fruits can contaminate farm machinery, vehicles, agricultural produce and garden waste, though these are thought to be minor spread pathways.

Control options

  • Pull or grub seedlings, and remove larger plants mechanically where practical.
  • Remove the entire crown and the top few centimetres of root to reduce regrowth.
  • For larger plants, cut stems near ground level and paint or swab the base with registered herbicides, or drill and fill the trunk.
  • Small plants are susceptible to spot spraying; overall spraying is not reliable. Follow product labels and use approved methods.

Hygiene and washdown

  • Check farm machinery, vehicles, agricultural produce and garden waste for Hawthorn fruits, and clean them before moving material to another site.
  • 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): No national listing. Managed under state and territory law.
  • 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: Regional priority in 1 of 11 regions. Regional priority weed in North West. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Regionally controlled / restricted weed (varies by region). Where it is regionally controlled, landowners must take all reasonable steps to prevent its growth and spread on their land. Where it is a restricted weed, trade in it (including the plant, its seed or contaminated material) is prohibited.
  • South Australia: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • 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: Declared pest, prohibited. It is a declared pest throughout the ACT. Dealing with it, such as selling, moving or keeping it, is prohibited.

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
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources