Quick Facts

Quick facts

• Originally from Europe and Asia, Cleavers (Galium aparine) is an annual, fast growing scrambling herb with rough course stems and leaves with small flowers ad sticky fruit 3–4 mm long and wide.
• A fast growing smothering herb that has been reported as a weed of crops, gardens, roadsides and native vegetation.
• It has hooked hairs on the stems and fruits that enable it to cling to fur and clothing and in this way dispersed to new sites.
• It has been detected as a contaminant in some crop seed lots.
• It resembles other weedy species of Galium (G. spurium and G. tricornutum) and several native species of the related genus Asperula.
• Small infestations can be controlled  by physical removal when young, or more commonly and easily controlled by herbicides.

What Does It Look Like?

What is it?

Cleavers (Galium aparine) is a scrambling or climbing annual herb with weak, multi-branched, four-angled course stems, growing up to 1.5 m long that are covered by small backward-pointing coarse hooked hairs or prickles along ridges and long simple hairs at nodes. The leaves are in whorls (rings) of six to nine around the stems, without a leaf-stalk. They are mostly 10–70 mm long and 2–10 mm wide, oblanceolate (slightly broader above the middle and tapering to a pointed tip). They also have small backward-pointing coarse hooked hairs (similar to those of the stems) on their upper surface, margins, and midrib on the lower surface.

The white flowers are inconspicuous, in loose stalked clusters, mostly 2–7-flowered, arising from the rings of leaves toward the tips of the branches, mostly exceeding the leaf-whorls on peduncles (main flowering stem) to 2.5 cm long with individual flowers borne on pedicels (individual flower stalks) to 1.5 cm long. The flowers are 1.5–2 mm wide and each of the four triangular petals are white, about 1 mm long.

The fruits 2–4 mm long develop soon after the flower opens and consist of a pair of joined spherical nutlets each 2–3 mm in diameter and is densely covered with short hooked bristles (Jeanes 1999). The prickles on the stems and leaves allow the plant to cling to other plants or objects that it comes in contact with, while the bristly fruits readily cling to clothing and animal fur (Jeanes 1999) aiding distribution.

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

Flower colour

White

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Cleaves prefers acid to neutral soils, but its prevalence as a weed of waste sites and gardens in the eastern states suggests it is tolerant of a wide range of soil pH and fertility (Western Australia Department of Agriculture and Food 2007). Specimen records show it occurs on sandy soils, clay loams, basaltic clays, soils derived from limestone, and alluvium (National Herbarium of Victoria 2007). It is a common weed of roadside ditches and occasionally flooded riverbanks (National Herbarium of Victoria 2007) and most riparian areas.

Are there similar species?

Other introduced members of Galium may be confused with Cleavers, the most similar being G. spurium and G. tricornutum. 

Galium spurium can be distinguished from Cleavers by its yellow or yellow-green (rather than white) flowers and the absence of a ring of fine hairs around the stems at the leaf bases (Toelken 1986). 

Galium tricornutum lacks hairs on the upper surfaces of the leaves and on the fruit. 

The other introduced species of Galium are much smaller and/or finer than Cleavers and have different fruit. Some native Galium species have hairy fruits, but all have leaves in rings of four. The related genus Asperula includes two native species, A. conferta and A. euryphylla, with leaves in rings of six or more, and with short hooked hairs on the stems, but the fruits of both these species are smooth (James & Allen 1992; Jeanes 1999).

Why Is It A Weed?

What are its impacts?

Cleavers is predominantly a weed of waste land and gardens, but occurs in crops and in some native vegetation types, with a preference for degraded or disturbed areas.

Agriculture: Cleavers is a major weed of canola overseas. It is a competitive climbing plant that forms dense masses of tangled vegetation in crops, along fence lines and on waste land. The size of the seed makes it difficult to separate from canola during seed cleaning (Western Australia Department of Agriculture and Food 2007). Although the weed commonly occurs in vegetable crops, beets, pastures, vineyards and plantation crops, it is most troublesome in cereals, where it may cause large yield reductions, interfere with harvesting, cause lodging, and in some instances smother the entire crop (CABI 2021).

Native ecosystems: It has also been regarded as an environmental weed (Swarbrick & Skarratt 1994). In Victoria, it has been described as a 'very serious threat to one or more vegetation formations' (Carr et al. 1992).

How does it spread?

Cleavers is an annual plant germinating in autumn spread by seed. Seeds are dispersed by wind, water, on the plant and especially by people or animals. The seeds survive in the soil for up to three years. It prefers acid to neutral soils, but may well grow on other soil types under less favourable conditions. The hooked bristles on the stems, leaves and fruits of Cleavers are able to cling to clothing and animal fur enabling it to be spread by humans and animals, while the seed has been included as a contaminant in Canola imported from New Zealand (Western Australia Department of Agriculture and Food 2007).

What is its history in Australia?

Cleavers was established as a weed in Australia by 1866 (Bentham 1866), presumably as a contaminant in imported seed, or attached to animal fur. In Western Australia (where it is only weakly established) it was introduced as a contaminant in canola seed in 1996 (Western Australia Department of Agriculture and Food 2007), however there is evidence of previous, possibly unsuccessful, introductions in Australia as early as the mid-1800s (National Herbarium of Victoria 2007). The first herbarium records are from Tasmania and Victoria in 1894 and 1895 respectively (AVH 2021)

How To Manage It?

Best practice management

Non-chemical control: Small infestations may readily be hand-pulled before seed set (plants are weak-rooted and are easily removed).

Chemical control: Easily controlled by herbicide application. There are numerous herbicides available in Australia that are suitable for chemical control of larger infestations (Western Australia Department of Agriculture and Food 2007; Herbiguide 2021).

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)

Cleavers is an annual (a plant that completes its life-cycle and dies within one year). The seed generally germinates in autumn, and depending on growing conditions, may flower as early as April. Peak flowering and fruiting occurs between October and January (Jeanes 1999; National Herbarium of Victoria 2007). The seed may survive in the ground for up to three years (Western Australia Department of Agriculture and Food 2007).

Where Is It Found?

Which states and territories is it found?

ACT, NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

Cleavers occurs in eastern Australia from south-eastern Queensland (Brisbane area), through much of New South Wales, where it is more common on the coastal side of the Dividing Range and in the Riverina area. It also occurs in the Australian Capital Territory. It is fairly evenly distributed through most of the inhabited parts of Victoria, and in Tasmania it is common through human settlement areas. In South Australia it is scattered from the southern Flinders Ranges southeast to the Victorian border, and in Western Australia it has been recorded from a few areas in the northern wheat belt (e.g. Paynes Find, Wubin areas), in the south-west near Bridgetown, and on islands of the Recherche Archipelago (AVH 2008; AVH 2021).

Where does it originate?

Cleavers is native in much of Europe through to central Asia (Jeanes 1999).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

WA

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

Galium aparine

Other scientific names (synonyms)?

• Galium aparina L. (incorrect spelling)
• Galium aparine L. var. aparine
• Galium aparine L. var. minor Benth.

Does it have other known common name(s)?

Goosegrass, Bedstraw, Clivers, Barweed, Burrweed, Catchweed, Catchweed Bedstraw, Robin-run-over-the-hedge, Stickywilly, Stick-willy, Sticky Willy, Sweethearts, Velcro Plant