Quick Facts

Quick facts

• Rough Corn Bedstraw (Galium tricornutum) is a scrambling stout annual with four-angled stems up to 1 m long, with whorls of leaves, insignificant white flowers, and small fruits.
• It is largely confined to, and may be a serious weed of, crops and pasture.
• Its mode of dispersal is apparently as a contaminant in crop seed or in stock fodder.
• It resembles other weedy species of Galium (G. aparine and G. spurium) and several native species of the related genus Asperula.
• It is a known host to the stem nematode which is a serious pest in lucerne crops.
• Small infestations can be controlled  by physical removal when young, or by careful selection of herbicides.

What Does It Look Like?

What is it?

Rough Corn Bedstraw (Galium tricornutum) is a scrambling course annual with four-angled stems up to 1 m long, that have small backward-pointing coarse hairs or prickles along the edges. The leaves are in rings of six to eight around the stems. The leaves are mostly 1–5 cm long and 0.1–0.5 cm wide, broadest above the middle and tapering to a blunt tip with a short central point. The upper surfaces of the leaves are smooth, but the margins and midrib and sometimes the lower surface have scattered tiny prickles.

The small white flowers are inconspicuous, borne in loose inflorescence (groups) of one to mostly three, arising from the upper stem nodes, inflorescence not exceeding leaf-whorls. The peduncles (main flower-stalk) is to 1.5 cm long, and pedicels (individual flower-stalks) are 0.1–0.8 cm long. The white flowers are to 1.5–2.5 mm wide with four triangular petals about 1 mm long.

The fruits develop soon after the flower opens and consist of a pair of joined, spherical nutlets, each 2–3 mm in diameter and usually densely covered with tubercles (small wart-like outgrowth) or papillae (small, elongated protuberance) resulting in a surface rough to the tough and bumpy looking (James & Allen 1992; Jeanes 1999).

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

Flower colour

White

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Rough Corn Bedstraw is mainly a weed of crops and/or fallow paddocks. Heavier infestations appear to occur in areas that have pulse crops incorporated into the rotation. It principally occurs on heavy alkaline soils with annual rainfall from 300 to 550 mm. It may be found in domestic gardens, but more frequently Galium aparine occupies this niche. It has also been reported from rubbish tips in New South Wales (James & Allen 1992; Western Australia Department of Agriculture and Food 2007).

Are there similar species?

Other introduced members of the Galium genus may be confused with Rough Corn Bedstraw, the most similar of these being the commoner and more widespread Cleavers (G. aparine) and the less common False Cleavers (G. spurium). 

Cleavers (Galium aparine), False Cleavers (Galium spurium) and Rough Corn Bedstraw (G. tricornutum) are easily confused, and all three species are characterised by the possession of robust backward-pointing hairs on stems and leaf margins. 

False Cleavers (Galium spurium ) can be distinguished from Corn Bedstraw (Galium tricornutum), by its white (rather than yellow or yellow-green) flowers. 

Cleavers (Galium aparine) has hooked hairs on the fruit; while the fruits of Rough Corn Bedstraw are slightly roughened by small granules, not smooth, and never have hooked hairs (Thompson 2008 in prep.).

The other introduced species of Galium are much smaller and/or finer than Cleavers and have different fruit. Of the eight alien species of Galium naturalised in Australia, all except G. palustre have a distinct see-through pointed leaf tip, a character not evident in the native species. 

Some native Galium species have hairy fruits, but all have leaves arranged in a ring of four.

The related genus Asperula includes two native species, Asperula conferta and Asperula 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).

Field Madder (Sherardia arvensis) is another member of the family Rubiaceae that may be confused with False Cleavers. It has stalkless, lilac to white flowers borne in tight clusters (Navie 2004).

Why Is It A Weed?

What are its impacts?

Rough Corn Bedstraw is a competitive climbing plant that can form dense tangled clumps, especially in crops but may occur away from crops on roadsides, and other areas. 

Agriculture: At high densities, Rough Corn Bedstraw can cause considerable yield loss in crops. It can be a troublesome in wheat, barley, field peas, chickpeas and faba beans, and can be difficult to control in other pulse crops.  Its seeds contaminate fodder and grain. It is a known host to the stem nematode, Ditylenchus dipsaci, which is a serious pest in lucerne crops (Western Australian Department of Agriculture and Food 2001; DPIRD WA 2021)

Native ecosystems: Can grow and to invade riparian and disturbed open vegetation.

How does it spread?

Rough Corn Bedstraw reproduces by seeds that are spread by water, wind, animals, machinery, on clothing, and in contaminated agricultural produce (Navie 2004). Its common occurrence in crop land and, given the first collection from Western Australia stated it had been inadvertently included with crop seed, this suggests contaminant in crop seed or stock fodder as a likely source of spread (Western Australian Herbarium 1998; Western Australian Department of Agriculture and Food 2007).

What is its history in Australia?

The first dated herbarium collection of Rough Corn Bedstraw is from Tasmania in 1896. The species is not now regarded as naturalised in that state (Buchanan 1999). It was subsequently collected in Queensland in 1888; New South Wales in 1899, South Australia in 1904, Victoria in 1966 and Western Australia in 1968 (AVH 2008; AVH 2021). In virtually all instances, where recorded, plants were growing in crop or pasture. It seems likely that it was initially introduced as a contaminant in grain or seed. The 1968 collection from Western Australia includes a claim that it originated from seed imported from the United States of America (Western Australian Herbarium 1998).

How To Manage It?

Best practice management

Non-chemical control: Small infestations of Rough Corn Bedstraw may readily be hand-pulled before seed set (plants are weak-rooted and are simply removed). Rough Corn Bedstraw can be treated and controlled as similar species Galium aparine (Cleavers) and False Cleavers (Galium spurium). Studies of Cleavers have shown that even minor tillage promotes the recruitment of Cleavers, and farmers might be able to reduce recruitment by limiting spring tillage (Reid et al. 2005). Farmers can also limit the spread of False Cleavers by practicing hygienic methods, such as cleaning machinery, using certified seed and clean tillage.

Chemical control: Herbicides are available that are suitable for chemical control in crop situations (Western Australian Department of Agriculture and Food 2007). There are effective herbicides for cereal crops and grass pastures, but it is more difficult to control bedstraw in canola, pulses and legume-based pastures (DPIRD WA 2021)

Please see Herbiguide 2021; and 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)

Rough Corn Bedstraw is an annual. The seed generally germinates in autumn. Peak flowering occurs between August and January (Toelken 1986). Flowers rapidly become fruit. Like the closely related Galium aparine, the seed is likely to survive in the ground for up to three years (Western Australian Department of Agriculture and Food 2007).

Where Is It Found?

Which states and territories is it found?

NSW, SA, VIC, WA

What areas within states and territories is it found?

Rough Corn Bedstraw occurs patchily in eastern Australia, from the Sydney region inland to near Mudgee, and in the south-west, in New South Wales. 

In Victoria it is confined to the west between Mildura and Kaniva.

In South Australia it is abundant on the Yorke and Fleurieu Peninsulas and has also been collected from just east of the Flinders Ranges, Kangaroo Island, and the south-eastern corner.

In Western Australia it has been reported from near Merredin (300 km ENE of Perth), Boddington (120 km SSE of Perth) and Cranbrook and Mt Barker areas toward Albany (Western Australian Herbarium 1998; AVH 2008).

Where does it originate?

Rough Corn Bedstraw is native through 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?

TAS, 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 tricornutum

Other scientific names (synonyms)?

Galium tricorne Stokes

Does it have other known common name(s)?

Three-horned Bedstraw, Three-horn Bedstraw, Three-cornered Bedstraw, Bedstraw, Cleavers, Corn Cleavers