Quick Facts

Quick facts

• Originally from Europe, north Africa and Turkey, Nettle Tree (Celtis australis) is a deciduous tree growing to 20 m.
• It is cultivated as a shade or street tree in the Australian Capital Territory, New South Wales, Victoria and South Australia.
• Occasionally naturalised in gardens and other areas near cultivated trees.
• Can invades woodland, urban areas, river margins and pine plantations.
• The ripe orange to purple-black fruits contain the seeds mainly spread by birds.
• Can be treated by mechanical removal and herbicides.

What Does It Look Like?

What is it?

European Nettle Tree (Celtis australis) is a deciduous tree growing to 15 m tall sometimes to 20 m. Crown is broadly rounded with dense foliage, bark grey-brown becoming flaky with age, older trunks are fluted to slightly buttressed. Twigs mostly drooping, young twigs pubescent (downy; covered with short, soft, erect hairs), new growth more or less tomentose (a dense covering of short woolly hairs). Leaves are petiolate (with a leaf-stalk) 8–20 mm long. Leaves are lanceolate (lance-shaped) to ovate-lanceolate (ovate: shaped like a section through the long axis of an egg and attached by the wider end), 40–130 mm long and 10–55 mm wide, with an asymmetric (uneven parts that fail to correspond to one another in shape, size) base, with finely toothed margins sometimes double toothed with alternate small to larger teeth, and a slender twisted point at the tip. The upper surface is deep to dark green with short stiff hairs and giving the leaf a rough feel. The lower leaf-surface is grey-green and covered with short, soft hairs on the leaf and veins. The leaves become creamy-yellow in autumn. They are prominently 3–5-veined from the base. 

Flowers are monoecious (having the male and female reproductive structures in separate flowers but on the same plant) sometimes bisexual (flowers with both male and female structures). Small flowers are produced singularly or in groups of 2-3 on pedicels (flower-stalks) 10-20 mm long, produced in the leaf axils (between the stem and leaf). Flowers are greenish-yellowish, have no petals. Male flowers c. 3 mm long, sepals 2–3 mm long, glabrous (without hairs) apart from the base, with 5 stamens. Female flowers to 7 mm long, sepals 2–3 mm, stigma bifid (with two main parts at the tip), to 4 mm, pubescent (downy; covered with short, soft, erect hairs). Bisexual flowers as female flowers, with 5 stamens.

Fruit (often called hackberries) is globose (round) and fleshy, about 10 mm diameter, starting yellow-green and turning orange to indigo, purple then nearly black when ripe, and on a stalk about 30 mm long (Blood 2001; Brodie et al. 2016; Harden 2000;  Henderson 2001).

For further information and assistance with identification of Nettle Tree, contact the herbarium in your state or territory.

Flower colour

Yellow, Green

Growth form (weed type/habit)

Tree

Where it currently grows? Preferred habitat

In Africa, Nettle Tree (Celtis australis) is not common, but it is widely distributed at medium to higher altitudes in evergreen rainforests, wooded ravines, riverine fringes, on rocky outcrops in high rainfall areas, and sometimes on termite mounds in the coastal forests in South Africa . It is tolerant of a wide range of soils, preferring deep loamy silts and clays. It can also survive on shallow, gravelly and rocky sites. It cannot grow in the shade but it does tolerate frost and drought. Seeds germinate well in cultivated well watered gardens with rich free draining soil. Where it is cultivated as a street tree in temperate areas, it matures to an ideal compact size and provides dense shade in summer. Many seedlings germinate in gardens, parks, roadsides, verges and wasteland. Occasionally found in areas of natural vegetation with parent trees in the vicinity (Brodie et al. 2016). It is grown as shade or street tree but has been spread by birds and now invades woodlands, urban rivers and forests (NSW DPI 2019).   

Are there similar species?

Nettle Tree (Celtis australis) is similar in appearance to other introduced Celtis species but may be distinguished by the toothed leaves, few-flowered clusters, the rough upper surface of the leaves and the pale, almost white, softly hairy lower surface, and purple to black fruit (Harden 2000).

Why Is It A Weed?

What are its impacts?

European Nettle Tree (Celtis australis) is used as an ornamental plant to provide shade and shelter and it is an ideal street specimen (Blood 2001) especially in urban areas as it is resistant to air pollution and is very long lived (Ciceran 2007). They are planted around cultivated fields as a boundary and for shelter and support. In Australia, Nettle Tree invades woodland, urban areas, river margins and pine plantations (Blood 2001). In South Africa, the Nettle Tree invades urban open space and river banks (Henderson 2001). The pollen is moderately allergenic (Ciceran 2007).

Nettle Tree timber is very tough, pliable and durable, and widely used by turners. The flexible thin shoots are used as walking sticks. The wood makes an excellent fuel (Ciceran 2007). Nettle Tree leaves are eaten in soups and salads. The fruits are edible and pleasant tasting (Blood 2001) and oil can be obtained from the seeds (Ciceran 2007). Extracts of Nettle Tree leaves and fruit are used medicinally to improve digestion and appetite, relieve pain and as an astringent (Ciceran 2007). Extracts are also used as a vermifuge (a substance that expels or destroys intestinal worms) and to treat oedema, headache and boils. The leaves and fruit are gathered in early summer and dried for later use. The fruit, particularly before it is fully ripe, is considered to be more effective as a medicine (Ciceran 2007).

Agriculture: Not a known weed of Agriculture, but may self seed around the margins if mature plants are present. Leaves and twigs are lopped for fodder in the dry season. The quality of the leaves is reported to be high, with 15% crude protein, good palatability and digestibility. The inner bark yields a tough fibre used in ropes and for weaving mats and yields a yellow dye (Blood 2001).

Native ecosystems: Known to grow in open woodlands and on the edge of native woodlands, and urban bushland, and other vegetation. Also a weed of woodlands, urban rivers, and forests (DPI, NSW 2019). Naturalised in the sub-coastal districts of NSW (Queensland Government 2016).

Urban areas: Where it is planted as an ornamental or street tree, plants can germinate in gardens and parkland ad if left can become large problematic woody weeds. 

How does it spread?

Nettle Tree mainly  reproduces by seed, and it may sucker. The seed is spread by birds, and possibly fruit bats. It is also sold at nurseries and garden centres (Blood 2001).

What is its history in Australia?

Nettle Tree (Celtis australis) was recorded as growing in the Melbourne Botanic Gardens, Victoria in 1921.

How To Manage It?

Best practice management

For European Nettle Tree (Celtis australis), there is no specific information available on control, however, techniques used for other weedy tree species are likely to be successful, such as physical removal and treatment with herbicides by stem injection and cut stump application.

Chemical control: Herbicide control is effective using the cut stump, basal bark or stem injection techniques. The method used depends on the site situation, tree size, access and personal preferences. Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Non-chemical control: Manual removal of isolated small seedlings can be attempted by hand pulling or digging them up. This is only practical for a small number of plants. Large trees may be cut down and the stump dug up and removed. Care should be taken to avoid moving fruit to un-infested areas when manually removing mature trees.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Old leaves of the Nettle Tree are shed at the beginning of winter and new ones appear simultaneously with the flowers in spring. Fruits ripen in autumn (Jäger 2004; ICRAF undated). The Nettle Tree is wind-pollinated (ICRAF undated).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, SA, VIC.

What areas within states and territories is it found?

Nettle Tree (Celtis australis) occurs in the Australian Capital Territory, New South Wales, Victoria and South Australia, where it is cultivated as a shade or street tree, as well as Queensland (Blood 2001; AVH 2008). It is rarely naturalised in Australia (Harden 2000).

Where does it originate?

Nettle Tree (Celtis australis) originates from; Albania, Bulgaria, Greece, Italy, Romania, Yugoslavia, France, Portugal and Spain in south-east and south-west Europe; Algeria, Morocco and Tunisia in northern Africa; and Turkey in south-west Asia (GRIN 2021).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

ACT

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

Celtis australis

Other scientific names (synonyms)?

Does it have other known common name(s)?

Southern Nettle Tree, European Hackberry, Lote-tree, European Nettletree, Honey-Berry, Sugar Berry