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Chinese celtis (Celtis sinensis)

Introduced as an ornamental and shade tree, Chinese Celtis is now a serious environmental weed in south-east Queensland and north-east New South Wales. It can form dense thickets along waterways, crowding out indigenous plants and affecting habitat.

Key facts

Type: Weed, tree.

Native to: China, Korea and Japan.

Established in: QLD, NSW.

Other names: Celtis, Chinese Elm, Hackberry, Japanese Hackberry.

Identification

  • It is a deciduous shrub or tree, usually up to 15 m tall, but rarely reaching 25 m, with smooth silvery-grey bark.
  • Its dark-green leaves are 4–10 cm long and 2–4.5 cm wide, oval and attached to the stalk asymmetrically.
  • The leaf margins are toothed mainly in the upper half; the upper surface is shiny and mostly hairless, while the paler underside has hairs on the veins.
  • Cream flowers appear from late winter to early spring, followed by globe-shaped orange or orange-brown fruit, 6–8 mm long, on stalks 4–10 mm long.
  • Look-alike: Chinese Elm (Ulmus parvifolia) has narrower leaves with finely toothed margins and dry fruit with a flattened wing.
  • Look-alike: Nettle Tree (Celtis australis) has sharply toothed leaves and dark purplish or nearly black fruit; the native Silky Celtis (Celtis paniculata) has entire leaf margins and blackish fruit.

Where it grows

In Australia it occurs in damp coastal areas, especially along waterways and near rainforest, and favours disturbed sites and clay soils.

Why it matters

  • It can rapidly form dense thickets that dominate riverbank vegetation and prevent regeneration of indigenous riparian plants.
  • Habitat destruction can negatively affect associated indigenous fauna.
  • Dense infestations can compete with crops and pastures for scarce irrigation water and moisture.
  • As a large, invasive tree, it may impede stock access, especially to waterways.

How it spreads

  • Seeds are spread by birds, fruit bats and water.
  • Old, mature, heavily fruiting trees in gardens are a major source of seed spreading into urban bushland.
  • Fruit-eating birds can spread Chinese Celtis alongside Camphor Laurel into disturbed riparian areas.

Control options

  • Hand-pull or dig out seedlings under 30 cm tall; this is practical mainly for small numbers of plants.
  • Large trees can be cut down and the stump dug up and removed.
  • Registered herbicides are used with methods including stem injection, basal bark application, cut-stump treatment, spot spraying and foliar spraying.
  • Identify and remove old fruiting garden trees, and control Chinese Celtis and Camphor Laurel concurrently to reduce the chance that one replaces the other.

Hygiene and washdown

  • When removing mature trees, take care not to move fruit into areas that are not infested.
  • 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: Restricted matter, category 3. Do not give it away, sell or release it into the environment. 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 Coast. 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.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development

Sources