Holdfast GT


  • Grazing tolerant winter active phalaris bred by the CSIRO
  • Holdfast GT exhibits excellent seedling vigour to aid successful establishment
  • Selected for long term persistence under grazing (both set stocking and rotational grazing)
  • Increased productivity over the life of the stand
  • Lower levels of stagger causing alkaloids
  • Its ability to grow in acidic conditions increases it’s area of adaptation

    Download a copy of the Holdfast GT Phalaris factsheet.


    Holdfast GT (Phalaris aquatica) was developed by the CSIRO and is a semi erect, winter active variety which forms thick, dense tufts of wide blue/green leaves that are very palatable to sheep and cattle. It has a low level of summer dormancy, so it can respond and take advantage of any summer rainfall should it occur. Holdfast GT was selected as a superior replacement for Holdfast, due to its outstanding winter production and persistence over this variety. It has excellent seedling vigour, which makes it a variety that can establish quickly and easily.

    This is very important for easier management of the stand, should there be a high level of weed competition. Once established, Holdfast GT will be able to handle periods of waterlogging and inundation. An advantage of Holdfast GT is its ability to grow in acidic conditions. It will also extend the range of pasture species to help combat soil degradation. Many farmers allow annual grasses to grow instead of establishing a perennial pasture based on Phalaris. Apart from being less productive, annual grasses play a role in the acidification cycle of soils. Nitrogen produced by pasture legumes usually grown with these grasses leaches down though the soil profile taking nutrients with it and leaving acidic elements behind.


    The deep rooted nature of Holdfast GT Phalaris draws these nutrients back up to the top of the soil, where they can be used and either prevent / slow down the onset of acidification. Another major benefit from the plants deep roots system is that it makes Holdfast GT very persistent under drought conditions.



    Key Benefits:

    CSIRO released Holdfast GT as a grazing tolerant replacement for Holdfast. It has been bred from Holdfast and other winter active varieties. Once established, Holdfast GT can be set stocked and will provide a productive long term stand. Holdfast GT also has a low alkaloid profile, very good autumn vigour and winter growth.


    Disease Resistance/Tolerance:

    Disease issues are very rare amongst established stands of Phalaris.


    Pest Resistance:

    Phalaris pastures can be seriously damaged by Blue Oat Mites (Penthaleus major), Red Legged Earth Mites (Halotydeus destructor), Field Crickets (Teleogryllus commodus), Pasture Scarabs (seriecsthis spp.), Slugs and Snails. Appropriate management of these insects is vital for successful stands, particularly during the establishment period.


    Variety Management / Agronomy:

    Grazing of new sown pasture should be avoided until plants have established themselves. Grazing plants too early can mean that plants are pulled out and thus reducing the plant population. Many of the older phalaris varieties have high levels of Alkaloids which can cause Phalaris staggers. Newer developed varieties such as Holdfast GT contain lower levels of Alkaloids in the leaves and therefore provide a safer grazing alternative. However in areas prone to Phalaris toxicity, plants should be grazed cautiously in the autumn and early winter. Holdfast GT can be grown with other legume or grass species to help reduce the risk of illness. Phalaris toxicity, or Phalaris staggers can affect sheep that are grazing on fresh breaks of Phalaris. Stock are most suseptible to Phalaris toxicity on short, frosted plants, which mainly occurs during the autumn or early winter period. To counteract the potential problem, stock can be orally administered with Cobalt bullets and also by ensuring that stock are not hungry when introduced to lush, green feed. The greatest risk to animals is when they ingest a high level of toxic herbage quickly. Toxicity levels in the plant can also increase if plants are subject to various stresses such as drought and frost.


    Once stands are established, it is recommended that you follow the following points to maximise the benefits and persistence from your Phalaris stands:

    • Lime acid surface soils if CaCl2 extractable Al is 8+ppm
    • Apply superphosphate if Olsen P is 8 ppm or less
    • Do not heavily graze new stems from summer regrowth
    • Clean up stem residues in summer to increase clover germination and growth
    • Do not crash graze or graze hard and often after stem growth starts in spring, especially in a dry year.





    A deep-rooted, vigorous perennial that is best suited to heavier soils, but will produce well on a range of soil types. Early varieties were most suited to neutral and alkaline soils, although newer varieties have been developed to produce well in more acidic conditions.