Herbicide responses of mat-forming weeds of forest remnants in New Zealand

Tradescantia fluminensis, Plectranthus ciliatus, Asparagus scandens, Hedera helix, Lamium galeobdolon and Selaginella kraussiana are all mat-forming weeds that interfere with the regeneration of native plants in forest remnants in New Zealand. Experiments carried out on potted specimens showed that low rates of triclopyr were effective in defoliating T. fluminensis, A.scandens, and L.galeobdolon but a higher rate was required for H.helix. Diquat was effective in defoliating P.ciliatus but the plants soon recovered. Aminopyralid was effective against S. kraussiana but was very slow acting. These experiments have identified herbicides that are effective against key mat-forming weeds at sufficiently low application rates to potentially be useful weed management tools for enabling native plants to re-establish in weedy native forest remnants in New Zealand.