A perennial that is often found in damp pastures. The flowers are purple and will appear in late summer (Jan-Mar).
Treating late in the growth stage seems to give the best results (ie) when fully vegetative through until flowering. (November to February)
The weed has a very distinctive 'minty' smell when the leaves are crushed between your fingers and is an easy method of positive identification.
Established pastures - 5-6L/ha 2,4-D Amine herbicide is the suggested treatment. This will give approximately 60 - 70% control. It has also been found that Pasture-Kleen* herbicide applied at 4-5L/ha is equally effective.
Poor results are obtained if MCPA herbicide is used.
No clover selective option is available (ie) MCPB, Select* and Preside* herbicides are ineffective against Pennyroyal.
Tordon* Gold will provide good control when applied through a knapsack as a spot treatment. The standard use rate for a knapsack of 12ml/L should be used. No additional wetter is required.
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