Pasture plant species for wet areas

Keep an eye out for sightings

Tablelands Telegraph – August 2021

Clare Edwards, Senior Land Services Officer – Pastures

Many Central Tablelands areas are experiencing wet pasture and soil conditions this season. This is partly due to rainfall, but also due to a lack of evaporation and reduced water use by plants. Low soil and air temperatures are limiting pasture growth, even in the species that can grow at low temperatures such as ryegrass and brome. Cold temperatures are also limiting growth and germination in newly sown pastures, with landholders commenting on the slow growth in these paddocks.

Sometimes these conditions are not immediately evident, but there can be clues in certain ‘indicator’ plants. Some species that we see in our pastures will favour depressions, drainage lines and swampy areas. These include pinrush, sedges, docks, toadrush, yorkshire fog, white clover, fescue and ryegrasses. Some of these species are useful for livestock production and some have alternative value in soil stabilisation and water quality filtering.

Broadly speaking, the following species are the most likely to be found:

  • A number of different varieties of rushes, or Juncus species. The pinrushes can typically be distinguished by their hollow stems. These are generally found in wet areas, drainage lines or depressions. They can be commonly found on the edge of dams and waterways. Toad rush (Juncus bufonius) is often confused with Rats-tail fescue/silver grass (Vulpia spp.). Toad rush is not a true grass and has no ligule. It can form a dense mat and has very small red-brown seedheads. There also a few different sedge species that we see on the Central Tablelands that are distinguished by a triangle-shaped stem. These can also look a bit like grasses too. Carex (tussock sedge) is a common sedge species.
  • Docks (Rumex spp.) have a rosette base, with upright stem that often has clusters of green-red-brown flowers. Sometimes, these are confused with the introduced herb chicory. However, chicory does not usually stay green in winter and it does not really like very wet areas.
  • Yorkshire fog (Holcus lanatus), an introduced cool season perennial grass (sometimes referred to as a weed), is quite common in wet areas. It can form a dense mat and become a monoculture. The leaves are hairy and velvety to feel. The seedhead can look like phalaris to start with and is often pinkish when young. The seedhead opens as it matures and becomes straw colour later in development.
  • Tall Fescue (Festuca arundinacae) is another cool-season introduced perennial pasture plant. This species is often sown into pastures and is more likely to have persisted in the wetter areas of the paddock. Some species can produce large tussocks. Recognition features of this species include parallel veination on the leaf and a seedhead that occurs in late spring – summer. Some new varieties are bred to be dormant over summer.
  • Ryegrasses (Lolium spp.) including annuals, perennials and hybrids are common in wet and more fertile areas. A distinguishing feature is the shiny back of the leaf and very green colouring. Perennial ryegrass is more tussock-forming than an annual ryegrass which is more upright.
  • Paspalum (Paspalum dilatatum) an introduced tropical perennial grass is very common in wet areas and often seen in pastures in wet summers. Common reed grass (Phragmites australis) is another species occurring in wet areas and in drainages areas on the side of the road. It is often referred to as a tall growing grass, 2- 4 metres in height.
  • White clover (Trifolium repens) is a cool-season perennial legume that commonly persists in wet areas. Sometimes it was sown in the pasture mixture or is now naturalised in these areas. In cool, wet summers white clover can be a valuable legume when the sub-clover has died off. While its features can vary, white clover typically has no hairs (sub-clover is hairy) and displays round leaves with white crescent markings. It can grow from seed or by putting out stolons. In hot, dry summers, there can be stolon death and the amount of feed produced by white clover can be limited. It is considered an aerial seeder with classic white-pink flowers. There can also be other legumes found in wet areas including lotus, strawberry clover and balansa clover.

These wet areas can be very useful in drier seasons. However, it is also important to manage them sensibly in wet times like this year.

Pugging by livestock can have detrimental effects on soil structure and soil health. This compaction can last for a number of seasons in some soil types. This, in turn, can reduce overall production from these areas.

So, consider your management strategies for these areas in a season like the one we are seeing this year.

Sometimes, these wetter areas can be dominated by native species like rushes and the native micolaena grass, poa, lomandra and native shrubs (eg tea tree). High elevation swamps and bogs may have important environmental aspects such as holding water within the landscape, helping to improve water quality, and providing habitat for threatened species including giant dragonflies, water skinks and important fauna such as frogs and crayfish.

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