Weed Action Plan

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The Torbay Catchment Group has been meeting to work out how to tackle weed control in the catchment. It has targeted key weeds, areas and strategies to be most effective. People have taken on responsibility for specific actions. We need your help.

WATSONIA - key target

Watsonias are tufted herbs with erect sword shaped leaves to 1 Metre in length, which are produced annually from a corm. Native to South Africa, now common in the South West, they are serious weeds of roadsides, watercourses and railway lines and often invade bushland. They reproduce from a large corm and small bulbils that are mainly at the base of the leaves but occasionally found up the flower stork.

Watsonia Control Options

  1. Grazing (may be toxic to horses) provides effective control, as is cultivation up to 100 mm if done after the old corm is exhausted and before the new corms form or before the flower stem emerges. Mowing and slashing are usually ineffective.

  2. Plants can be dug up by loosening the soil with a fork then pulling the top growth and cormels. Be careful not to dislodge cormels. Burn cormels or bury more than 1000mm deep. Start with isolated plants and light infestations to stop spread of plants. Thick infestations are difficult to control manually.

  3. There are several options for control by spraying. There are different chemicals and a range of ways to apply them. It is suggested that large infestations are sprayed and then followed up for the next 2 years with hand swiping.

    Spraying - Large Areas -apply 10kg/ha of 2,2 DPA plus 25% non ionic wetting agent after flower stems emerge and before flowering (September to October) each year for 3 years. Many shrubs and trees are quite tolerant of DPA so it is a good treatment for overall spraying of roadsides. Smaller areas - use 1kg 2,2 DPA plus 250ml wetting agent per 100ml water for hand spraying. Spray until the plants are just wet and treat an area of soil about 1 metre diameter around the plant to help control cormels germinating next season.

    Or

  4. Spraying Apply 6 L/ha of Glyphosate (450g/l) plus 0.25% non ionic wetting agent when the flower stems first emerge (September) each year for 3 years. This is non selective and will kill most other plants sprayed. Hand spraying - Use 1 L Glyphosate plus 250ml wetting agent per 100 L of water for hand spraying. Spray until plants are just wet.

    Or

  5. Spraying In bush land or sensitive areas, apply a mixture of 1 part Glyphosate plus 2 parts water using a sponge (or sponge glued to a glove) and wipe a third or more of the leaves. Repeat this each year in late winter to early spring before flowering.

Equipment & Chemicals

Torbay Catchment Group has a spray unit for the back of a ute as well as a knapsack sprayer available for weed control by catchment landholders. Some chemicals are also available.

Contact

For further advice, and to access chemicals and spray equipment or to assist in the Torbay Catchment Group's control program by helping with spraying or hand swiping, please contact Andrew Marshall 9845 1081 or Phil Mellon 9844 6371 (A/H).

All assistance welcome

Reference: Moore J & Wheeler J, Southern Weeds and Their Control. Dept Ag, CALM.