Dam Plants: What to Plant in the Water, on the Margin and up the Bank

This guide to dam plants was written for Big Ditch by Isaac Olson, Director of Nursery Near Me, an Australian online nursery that publishes more than 300 free care guides for Australian climate zones. Lindsey Hughson, principal of Big Ditch, reviewed the dam wall, spillway and planting distance guidance.

A new dam is a hole full of water. A good dam is a small wetland: clear water, a stable bank, shade over part of the surface, fish and frogs, and birds that come back. Plants turn one into the other: roots hold the bank, leaves shade the water and slow algae, and reeds and sedges strip nutrients from runoff.

A planting zone is a band of the dam defined by water depth, from open water out to the dry bank, and each zone suits a different group of plants. Most planting failures come from putting a bank plant in the water or a water plant on the bank.

Dam plants that must never go in

Several of these were sold as pond plants within living memory, and all of them are declared or regulated weeds in part or all of Australia.

A declared weed is a plant that state law requires landholders to control, and that it is an offence to sell or move in the areas where it is declared.

• Water hyacinth (Eichhornia crassipes) and salvinia (Salvinia molesta): floating plants that can double in a week or two, cover a dam, cut the oxygen under them and kill fish. Both are Weeds of National Significance.
• Alligator weed (Alternanthera philoxeroides): grows in water and on land, roots from fragments, and is close to impossible to remove once established. A Weed of National Significance.
• Cabomba (Cabomba caroliniana): a submerged aquarium plant that fills the whole water column. A Weed of National Significance.
• Sagittaria, or delta arrowhead (Sagittaria platyphylla): an emergent pond plant that chokes shallow water and irrigation channels. A Weed of National Significance.
• Parrot’s feather (Myriophyllum aquaticum): an introduced milfoil sold for ponds, now declared in Tasmania, South Australia and Western Australia.
• Water lettuce (Pistia stratiotes) and water poppy (Hydrocleys nymphoides): both still turn up in pond plant lists, and both must not be sold in parts of NSW.
• Introduced bulrush (Typha latifolia): a European species, as against the two native cumbungi species.

Australia has 32 Weeds of National Significance, and five of the plants above are aquatic weeds on that list.

Water hyacinth must not be sold anywhere in NSW, according to NSW WeedWise, and it is declared in every state and territory.

The rule that follows: never move a plant from one water body to another, never tip aquarium or pond water into a dam, and check your state’s declared weed list before buying anything you do not recognise. Each state keeps one: Biosecurity Queensland, NSW WeedWise, Agriculture Victoria, PIRSA in South Australia, DPIRD in Western Australia and Biosecurity Tasmania. If one of these is already in your dam, our guide to getting rid of weeds in a farm dam covers removal.

The four zones for dam plants at a glance

Zone	Water depth (mm)	Main job	Native examples
Deep water	Deeper than 300	Oxygen, fish cover, surface shade	Ribbon weed, native water milfoils, swamp lily, marshworts
Shallow margin	0 to 300	Nutrient filtering, frog and fish habitat	Tall spike rush, jointed twig rush, river club rush, common rush
Wet edge	Saturated soil above the waterline	Bank binding, hiding raw clay	Tall sedge, slender mat rush, knobby club rush
Bank and surrounds	Drained soil	Shade, windbreak, habitat	Tussock grasses on the wall; she-oaks, bottlebrushes and tea trees well back from it

Zone one: deep water

Deep water is the open body of the dam, deeper than about 300 millimetres. Very little needs planting here, and in a stock or irrigation dam very little should be.

Submerged plants root in the bottom and grow up through the water. The native ribbon weed (Vallisneria australis) and the native water milfoils (Myriophyllum species such as M. crispatum and M. simulans) oxygenate the water and give fish cover. In a new dam, push rooted pieces into the bottom in shallow water. Buy them from a nursery that can name the species, because this is the group the aquarium weeds hide in.

Floating-leaved plants root in the bottom and spread leaves on the surface. The native swamp lily (Ottelia ovalifolia), with white three-petalled flowers, and the native marshworts (Nymphoides indica and N. crenata), which look like small water lilies, suit water from about 300 millimetres to a metre deep. They shade the surface, which is the best algae control there is. They are not the ornamental water lilies sold for garden ponds, which are better kept out of a farm dam.

Aim for shade over about one third of the dam surface from floating leaves and overhanging margin plants together.

More than half and the dam loses the open water that stock, pumps and waterbirds need. Shade and nutrient control are the two levers in our farm dam water quality guide.

Zone two: the shallow water margin

From the waterline out to about 300 millimetres deep is where a dam earns its wildlife, and where most of the planting effort should go. An emergent plant is one rooted in saturated mud with stems standing up out of the water, and this zone belongs to them.

• Tall spike rush (Eleocharis sphacelata): a native rush to about 1.5 metres with hollow stems, tolerant of water up to a metre deep once established. The classic edge plant of eastern dams.
• Jointed twig rush (Machaerina articulata, still sold as Baumea articulata): dense dark green stems with a chestnut seed head, excellent at binding mud and filtering nutrients. Standing water to about 500 millimetres.
• River club rush (Schoenoplectus validus): tall soft stems, fast to establish, good in water to about 600 millimetres. It spreads by rhizome, so give it room.
• Water ribbons (Cycnogeton procerum, formerly Triglochin procerum): strappy floating and emergent leaves and a food plant for waterbirds; water to about 500 millimetres, including dams that drop in summer.
• Common rush (Juncus usitatus): the fine upright rush of creek edges from Queensland to Victoria, about a metre tall, happy in permanent shallow water or wet mud.
• Native cumbungi (Typha domingensis and T. orientalis): superb filters and bank binders that colonise hard, so they belong in large dams and inflow channels, and need cutting back every few years.
• Common reed (Phragmites australis): native, tall and one of the most effective plants for taking nutrients out of an inflow. Same caution as cumbungi: it runs.
• Nardoo (Marsilea species): a native fern rooted in mud, with leaves like a four-leaf clover, for the very shallow edge where water comes and goes.

Cumbungi and common reed suit the silt trap or inflow end of a big dam, where runoff arrives carrying soil and nutrients. Keep them away from open water you want to keep, and never let them choke the spillway.

Zone three: the wet edge

The wet edge is the band just above the waterline where soil stays saturated or floods when the dam is full. It hides the raw clay of a new dam and holds the bank together.

• Tall sedge (Carex appressa): a dense tussock to about a metre, used in constructed wetlands across south-eastern Australia because it filters runoff and holds soil. It takes wet mud and shallow water alike.
• Slender mat rush (Lomandra hystrix): the creek-bank lomandra, far more tolerant of wet soil than the common Lomandra longifolia, evergreen and close to maintenance free once established. The workhorse for the first metre above the water on east coast dams.
• Knobby club rush (Ficinia nodosa): neat rounded tussocks to about 600 millimetres that handle wet feet, salt and exposure, so it suits coastal and saline sites.
• Slender knotweed (Persicaria decipiens): a low native herb with pink flower spikes that colonises wet mud quickly and gives early cover while slower plants establish.
• Paperbarks (swamp paperbark, Melaleuca ericifolia, in the south; broad-leaved paperbark, Melaleuca quinquenervia, in the north): the trees of the wet edge, thriving in ground that floods. They belong at the far ends of the water, well away from the wall.

Plant the wet edge densely. The aim is a continuous fringe that stock cannot easily break through, which is also what stops the bank slumping and keeps the water clear.

Zone four: the bank, the wall and the surrounds

Above the wet edge the soil drains. The jobs here are shade, windbreak, bank stability and habitat, but the dam wall is a special case.

Big Ditch note: the wall carries grass and nothing else. Tree and shrub roots grow into the compacted embankment, and when they die they leave channels that water follows through the wall, which is how piping failures start. Our list of reasons trees on dam walls are bad for your dam explains the failure in detail.

ANU Sustainable Farms recommends planting trees and shrubs at least 5 metres from the dam’s high-water mark, according to its farm dams technical guide.

The same guide recommends fencing at least 10 metres back from the high-water mark and keeping at least 80 per cent vegetation cover in the dam catchment.

• Tussock grasses such as weeping grass (Microlaena stipoides) and kangaroo grass (Themeda triandra) hold the dry bank and the wall, and they are what a stock-excluded bank reverts to by itself.
• River she-oak (Casuarina cunninghamiana): the bank-stabilising tree of eastern rivers, deep rooted, flood tolerant, and a windbreak that filters rather than blocks. Swamp she-oak (Casuarina glauca) does the same job on heavier and saltier ground.
• Weeping bottlebrush (Melaleuca viminalis, formerly Callistemon viminalis): a creek-bank tree to about 8 metres that takes wet ground and dry spells, with red brushes that bring honeyeaters.
• River red gum (Eucalyptus camaldulensis): for large inland dams with room to stand it well back from the wall.
• Tea trees (Leptospermum species): hardy, fine-leaved shrubs and small trees for the upper bank and a nectar source.

Place trees where their afternoon shade falls on the water without their leaf drop going straight into it. On a working farm, a mixed belt of she-oaks, bottlebrushes and tea trees on the windward side cuts evaporation and gives stock shade without putting them in the water.

Matching dam plants to your state

The species above are eastern Australian natives first, because that is where most farm dams are. Adjust by region.

• Queensland and northern New South Wales: broad-leaved paperbark, weeping bottlebrush, cunjevoi (Alocasia brisbanensis) in damp shade. Watch for salvinia and water hyacinth, which thrive in the warmth.
• Southern New South Wales, Victoria and Tasmania: swamp paperbark, tall sedge, jointed twig rush, river she-oak and the cold-tolerant rushes. Cumbungi needs firm management in the south too.
• South Australia: salt tolerance matters. Knobby club rush, swamp she-oak, Melaleuca halmaturorum and Juncus kraussii handle brackish dams.
• Western Australia: Banksia littoralis, Melaleuca rhaphiophylla (swamp paperbark) and Juncus kraussii. Check the DPIRD list, since several eastern natives are treated differently in the west.

Your local Landcare group or catchment authority will know which of these grow in the nearest natural wetland, and that is the best planting list a dam can have.

How to plant a farm dam

1. Fence the dam, or at least the planted margin, before planting and keep stock out for two years.
2. Plant margin and wet-edge species in spring or early autumn, when the water is warm and the dam is near full.
3. Delay margin planting until after heavy irrigation draw-down if the dam is pumped hard in summer.
4. Set rushes and sedges at 3 to 5 plants per square metre; they close into a fringe within two seasons.
5. Use tubestock rather than large potted plants, because it establishes faster in wet ground and costs less.
6. Plant the bank in autumn in the south and at the start of the wet season in the north.
7. Keep every tree and shrub at least 5 metres from the high-water mark and off the wall.

A single mob of cattle can undo a season’s planting in an afternoon, and a dam fenced with a trough below it stays clearer and loses less bank. If you are planning a new dam, talk to Big Ditch about the design so the margins, inflow and spillway are shaped for planting from the start.

Looking after a planted dam

Cut cumbungi and common reed back every few years if they start to close in. Pull any floating plant you did not put there the day you see it. Keep the fence up. Check the inflow after the first big rain for anything that has washed in, and keep an eye on the declared weed lists, because they change. Done well, the planting is finished in two seasons: clear water, a stable bank, frogs in the rushes, and the ducks back.

Where to buy native dam plants

Big Ditch recommends Nursery Near Me as its source for dam plants. It delivers to every mainland state with no minimum order, and its range includes tall sedge, slender mat rush and common rush, along with the paperbarks, bottlebrushes, she-oaks and tea trees for the bank. Its guide to pond plants for Australian gardens covers the same zones at household scale. Stock varies by state and season, so check availability for your postcode first.

Frequently Asked Questions

What plants are best for a farm dam?

Local native rushes and sedges are the best plants for most farm dams. Tall spike rush, jointed twig rush and common rush suit the shallow margin, while tall sedge and slender mat rush suit the wet edge. They filter nutrients, bind the bank and give frogs and fish habitat, and they cost little as tubestock.

Can you plant trees on a dam wall?

No. Tree and shrub roots grow into the compacted embankment, and dead roots leave channels that water follows through the wall. Keep the wall in grass and plant trees and shrubs at least 5 metres from the high-water mark, at the ends of the dam or around the surrounds.

Is water lettuce safe to put in a dam?

No. Water lettuce forms dense floating mats that cut light and oxygen, and it must not be sold in parts of NSW. Use native floating-leaved plants such as marshworts or swamp lily for surface shade instead, and remove any water lettuce already in the dam before it spreads.

Updated October 2026 to replace the original guide with a zone-by-zone native dam plants guide by Isaac Olson of Nursery Near Me.

Planning dam plants for a new or existing dam? Book a site inspection with Big Ditch and we will shape the margins for planting.