Quick Facts

Quick facts

• Parodi Spike Rush (Eleocharis parodii) is a perennial sedge native to Argentina.
• It grows in wet places like irrigation channels and rice crops.
• In Australia, it is only known from one infestation near Griffith, New South Wales, which is now thought to have been eradicated.
• Potentially, it could spread to become a problem in man-made and natural wetlands in southern Australia.

What Does It Look Like?

What is it?

Parodi Spike Rush (Eleocharis parodii) is a slender tufted perennial sedge, with a short rhizome (underground stem). Flowering stems (culms) are 20–45 cm high, pith-filled, round in cross-section, and 2–5 mm in diameter. The leaves are reduced to brownish sheaths enclosing the base of the flowering stems.

The spike-like flower head is cylindrical, 2–3 cm long, 2–4 mm in diameter, and looks like a continuation of the stem. Floral bracts (modified leaves) are about 2 mm long, yellow-brown, with a broad translucent margin. The 6–7 whitish bristles are slightly shorter than the nut.

The pale brown or greenish grey nut (fruit) has 3 ribbed angles, is egg-shaped, about 0.8 mm long and about 0.5 mm in diameter. The small persistent style-base on top of the nut is about a sixth as long as and about a quarter as broad as the nut, and is separated from the nut by a narrow neck (Wilson 1993).

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

Flower colour

Yellow, Green

Growth form (weed type/habit)

Herb, Aquatic

Where it currently grows? Preferred habitat

Parodi Spike Rush grows in wet habitats, with at least semi-permanent water. This can include irrigation channels as well as natural waterbodies (Wilson 2007, pers. comm.).

Are there similar species?

There are numerous native species of Eleocharis (Spike Rushes) in Australia as well as several introduced species. All have a similar spike-like flower head and reduced leaves. Parodi Spike Rush can be distinguished from these other species by a combination of its overall size, closely packed floral bracts and nut size and shape (see Wilson 1993 for further details). Several native Eleocharis species are illustrated by Sainty & Jacobs (1981).

Why Is It A Weed?

What are its impacts?

Agriculture and native ecosystems: Potentially, Parodi Spike Rush could impact on irrigation channels and irrigated crops such as rice, as well as natural wetlands, in southern Australia (Cunningham & Brown 2006; Wilson 2007, pers. comm.).

How does it spread?

Dispersal of Parodi Spike Rush is likely to occur by nuts being eaten by water birds or being transported in water or in mud on birds' feet or on other animals or farming equipment. Dispersal could also happen by spread of displaced rhizomes in water or with mud (Sainty & Associates 2004; Wilson 2007, pers. comm.).

What is its history in Australia?

Parodi Spike Rush was probably introduced into Australia accidentally with contaminated rice seed or farming equipment (Wilson 2007, pers. comm.).

Parodi Spike Rush was first collected near Griffith, New South Wales, in 1977, where it occurred over less than 1 hectare. It has not been seen there since 2000. The irrigation channel where it was growing was filled in and replaced by a pipe in 2003 (Sainty & Associates 2004). In early 2006 it was considered to be eradicated but ongoing monitoring was recommended. It is not known to be naturalised elsewhere in Australia (Cunningham & Brown 2006).

How To Manage It?

Best practice management

Non-chemical control: Isolated plants can be removed manually, taking care to avoid knocking nuts out of the flower heads. If an infestation is found, control advice should be sought from local state or territory weed authorities (Wilson 2007, pers. comm.).

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)

Parodi Spike Rush is a perennial herb that flowers during spring and summer. The above-ground stems may die back in winter (Wilson 2007, pers. comm.).

Where Is It Found?

Which states and territories is it found?

NSW

What areas within states and territories is it found?

Parodi Spike Rush was first collected near Griffith, New South Wales, in 1977, where it occurred over less than 1 hectare. In early 2006 it was considered to be eradicated but ongoing monitoring was recommended. It is not known to be naturalised elsewhere in Australia (Cunningham & Brown 2006).

Potentially, Parodi Spike Rush could spread to other irrigation areas and wetlands in temperate mainland Australia and possibly Tasmania (Sainty & Associates 2004).

Where does it originate?

Parodi Spike Rush is a perennial sedge native to Argentina (Cunningham & Brown 2006).

It is not known to be naturalised anywhere else outside its natural range (Cunningham & Brown 2006).

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?

YES

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Eleocharis parodii

Other scientific names (synonyms)?

Heleocharis parodii Barros (incorrect spelling)

Does it have other known common name(s)?

Spike-rush