Quick Facts

Quick facts

• Tussock Paspalum (Paspalum quadrifarium) is a blue-green perennial grass growing in large tufts to 2 m tall.
• This South American plant has limited distribution in Australia, occurring mainly in the Sydney region and in a few localities along the eastern seaboard.
• Tussock Paspalum is found in neglected areas along roadsides, streams, wetlands and drains.
• The plant can rapidly and aggressively invade bushland, displacing native flora, changing fire regimes and providing shelter for feral animals.
• The most common method of control is to brush-cut the plant and spray with herbicide.

What Does It Look Like?

What is it?

Tussock Paspalum (Paspalum quadrifarium) is a perennial grass that grows in large bluish-green tufts, reaching 2 m in height. The leaf sheath is mostly hairless, as is the leaf blade which rolls inwards upon drying. The blade is 5–8 mm wide and the ligule (membranous structure where the leaf sheath and blade meet) is 1–3 mm long. Rhizomes (horizontal roots just under the soil surface) are absent or short (Jacobs & Wall 1993, Allen & Hall 2007, Clayton et al. 2007).

The flower head of Tussock Paspalum is 12–30 cm long with 15–40 branches of stalked flowers or spikelets on an elongated central axis. The branches are 1.2–8.5 cm long, straight and sloping upwards, the lower branches longer than those above. The flower spikelets are about 2.5 mm long, paired, in 4 irregular rows and are on 1 side of the branch. They are brown to straw-coloured, often tinged with purple (Jacobs & Wall 1993, Allen & Hall 2007, Clayton et al. 2007).

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

Flower colour

Yellow, Purple

Growth form (weed type/habit)

Grass

Where it currently grows? Preferred habitat

Tussock Paspalum is often found alongside streams, wetlands and drains and generally prefers neglected land of low fertility. It has the ability to grow on soils ranging from those that are very sandy through to compacted clay (Regional Weeds Advisory Committee 2006).

Are there similar species?

Tussock Paspalum can be mistaken for other grasses with similar looking seed heads, such as African lovegrasses (Eragrostis spp.) (Sydney-wide Big 4 Grasses Management Plan 2006–2011). Tussock Paspalum looks similar to Paspalum (P. dilatatum), a weed of lawns and seasonally wet areas, but can be distinguished by the short white hairs on the upper glume (modified small leaf) of the spikelet compared to the long silky hairs on the Paspalum spikelet (Jacobs & Wall 1993).

Distinguishing between grass species can be extremely difficult. The use of field guides with line drawings and/or photographs is recommended as well as the use of hand lenses or microscopes. Any samples being sent away for expert analysis, e.g., to a state herbarium, ideally need to have complete seed heads containing seeds as well as leaves for correct identification.

Why Is It A Weed?

What are its impacts?

Native ecosystems: Tussock Paspalum can grow to a large size forming almost impenetrable walls. In these situations, Tussock Paspalum dominates other vegetation including native plants. The displacement of native vegetation has serious implications for biodiversity of both flora and fauna (Regional Weeds Advisory Committee 2006).

Alive or dead, mature clumps are highly combustible and hence are able to change fire regimes. The clumps provide excellent shelter for feral cats and rabbits (Regional Weeds Advisory Committee 2006).

How does it spread?

Tussock Paspalum can rapidly spread through either rhizomes or seeds and aggressively forms extremely dense infestations in a few years. Rhizomes move horizontally sending up suckers which form a large, dense tuft. Numerous seeds then drop from this large plant forming new plants close by increasing the size of the tussock (Invasive.org 2007).

Seeds may be spread much further afield, by water, on animal fur, on clothing, in mud-encrusted boots, vehicle tyres and mowing machinery (Invasive.org 2007). A downhill run of water is ideal for the transmission of seeds and enables the plant to spread rapidly from disturbed edges into native bushland. The seeds are sticky at one point in their development and this aids their transfer to animals, people and machinery (Regional Weeds Advisory Committee 2006).

What is its history in Australia?

It is not known how or when Tussock Paspalum arrived in Australia, but early bush care volunteer observations indicate that the weed established in Delhi Park in Sydney's north in the mid 1950s. Its appearance coincided with circus companies which repeatedly occupied the site. The weed was contained within the park for a period of time because Ryde Council regularly mowed the grounds. However, in 1995 the mowing stopped and the weed went to seed and was spread by heavy machinery into areas outside the park. Since 1995 the weed has spread into adjacent Lane Cove National Park and along adjacent road verges (Regional Weeds Advisory Committee 2006).

How To Manage It?

Best practice management

Because of its size and the scale of some of the infestations, Tussock Paspalum can be difficult to control.

Chemical control: The most common method of control is to brush-cut the plant and then spray the regrowth with herbicide. Alternatively, some Local Council Authorities have achieved good success by spraying without the brush-cutting. Follow up work is almost always required as the plant can seem to be dead but then resprout a year or more after the initial treatment.

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au 

Non-chemical control: Manual control: Hand removal is possible and is most appropriate for scattered individuals or small infestations, particularly where the soil is sandy or friable (Regional Weeds Advisory Committee 2006). 

Fire: Warringah Council in New South Wales has successfully trialled burning of Tussock Paspalum clumps as a method for effective control (Regional Weeds Advisory Committee 2006); however, elsewhere in the world, such as Argentina, where cattle graze on rangelands comprising mostly Tussock Paspalum, fire is used to increase its growth and nutrient value (Vignolio et al. 2003).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Tussock Paspalum flowers mostly from spring to autumn but the flower heads seem to be present all year round (Jacobs & Wall 1993). It appears to flower and produce seed at least twice a year (Invasive.org 2007).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, VIC

What areas within states and territories is it found?

Tussock Paspalum has limited distribution in Australia, occurring mainly in the Sydney region and in scattered localities in Queensland (Gympie–Maryborough area and near Townsville) and Victoria (near Melbourne) (Mallett & Orchard 2002; Regional Weeds Advisory Committee 2006).

Where does it originate?

Tussock Paspalum is native to Uruguay, Paraguay, Brazil and Argentina (Invasive.org 2007).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, 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

Paspalum quadrifarium

Other scientific names (synonyms)?

Does it have other known common name(s)?

Goldentop Grass