Image: Cumbungi, © T Rudman.
What is cumbungi?
- Cumbungi (also known as bullrush) is a name given to a group of three similar plant species found in Tasmania. Cumbungi (Typha latifolia) is a weed,
(introduced from the northern hemisphere), while broadleaf cumbungi (T. orientalis) and narrowleaf cumbungi (T. domingensis) are native to Tasmania.
- Cumbungi is a troublesome weed of farm dams, creeks, ponds and slow moving rivers in Tasmania. The two native cumbungi are not weeds, but can sometimes become a problem in poorly managed dams and waterways on agricultural land.
How to identify cumbungi
- Cumbungi are semi-aquatic plants growing in lakes, dams, irrigation channels, marshes and rivers where the flow is slow and dissolved nutrient levels are high.
- The grass-like leaves are thick and spongy, and are borne on either side of a stout, cane-like stem growing to 2.5 m high. The flower head is produced in summer. Each stem produces one flower head divided into an upper spike of male flowers, and below this a cylindrical spike of female flowers.
- The introduced cumbungi (T. latifolia) can be distinguished from the two native cumbungi by the colour and size of the flower head.
- For the introduced cumbungi, the female (or lower and cylindrical) part of the flower head is blackish-brown in colour, 100-200 mm long and 15-30 mm in diameter.
- The female flower head of broadleaf cumbungi is chestnut-brown in colour, 100-200 mm long and 15 - 25 mm in diameter.
- The female flower head of narrowleaf cumbungi is cinnamon-brown in colour, 120-300 mm long and 6-15 mm in diameter.
- See the
Cumbungi Fact Sheet for more information in distinguishing between the three species. If you are in doubt about the cumbungi you are dealing with, contact Biosecurity Tasmania on 03 6165 3777 for help.
Cumbungi in Tasmania
- The introduced cumbungi is found throughout the State in farm dams, creeks, ponds and slow moving rivers. Cumbungi is continuing to spread in Tasmania as fertiliser and animal manures are washed into waterways, creating the nutrient-rich waters cumbungi prefers.
- Cumbungi can reduce the holding capacity and access areas of dams and waterways. In rivers, creeks, and irrigation and drainage channels, cumbungi can restrict and even block water flow. Destruction of the weed can also result in a large amount of decaying vegetation polluting the water and blocking pump intakes, channels and ditches.
Weed Links and ResourcesCumbungi Fact SheetOther useful links:Pest GenieAPVMA
Cumbungi (Bullrush) Control
Please note, cumbungi types:
Before you start clearing an infestation, make sure you are dealing with the introduced cumbungi, (see
Cumbungi Fact Sheet
for more information). The broad-leaf cumbungi and narrow-leaf cumbungi are native species and should not normally be removed. These native cumbungi can provide shelter for waterbirds and other aquatic organisms, as well as being useful for reducing erosion of river banks.
- Plan your control program, this will save time and money in the long-run;
- Consider the impact of your control methods on off-target species, especially if herbicides are used;
- Ensure machinery and equipment is washed down between sites or prior to contractors leaving site;
- Get in early - For new infestations, eradicate before the plants reach the flowering stage: once plants begin seeding, control becomes more difficult and expensive;
- Carefully time your use of herbicide for best results (see the
Herbicides for cumbungi control link for more information);
- Coordinate your control program with neighbouring landholders where your weed problem crosses property boundaries;
- Revisit and regularly inspect the site and ensure follow-up is undertaken;
- Consider a non-herbicide method first.
- Don't start your control program without first planning your approach;
- Don't allow an infestation to become established. Get in early!
- Don't rely on just one treatment: follow-up is essential.
Spread of cumbungi
- Cumbungi reproduces in two ways: long distance dispersal by seed, and the spread of dense infestations from rhizomes (underground stems).
- Cumbungi seed may be transported by wind and water, in mud on the feet of birds and livestock, and on machinery.
Avoiding the establishment of cumbungi
- Cumbungi quickly becomes a large and vigorous plant, so any new infestation should be treated as early as possible.
- Destroying young plants, before they establish and produce seed, is the most effective method of control.
- If an infestation becomes established, eradication in one season is difficult and follow-up work over two or three seasons will be required.
- Small plants can be removed by hand-pulling or with a spade. Make sure all pieces of the roots and rhizomes are removed, otherwise the plant can quickly regrow.
- Larger infestations can be removed by mechanical excavation. Care must be taken to avoid damage to the structure of the waterway.
- Excavated material should be dumped well away from the water at a site where it can dry out and kill all plants.
- Repeatedly cutting all leaves at 50-150 mm below the water surface can be used to control small infestations. First cut when the flowering period is well advanced (around January), with follow up cuts at 4 to 6 weekly intervals.
- Most plants will die in the first year using this cutting method. A second year of treatment should finish off any plants which survive the first treatment.
- If low water levels permit, an alternative to excavation may be to cultivate the site in autumn.
- This brings root and rhizome material to the surface to dry out. This method gives good control over small infestations, and can reduce the size of large infestations to manageable levels.
- A limited number of herbicides are registered for use on cumbungi in Tasmania due to problems with off-target effects on rivers. See
Herbicides for Cumbungi Control for more information.
- Using a herbicide has several disadvantages. The mass of decaying vegetation reduces a dam's holding capacity and can allow invasion by other weeds or a re-invasion of cumbungi.
- Use of a backhoe, bulldozer or dragline may be needed to restore the dam to its original capacity.
- Decomposition of the dead plant material can render the water unfit for use by stock.
Herbicides for Cumbungi (Bullrush) Control