New Zealand Journal of Forestry (1978) 23(1): 137–142
©New Zealand Institute of Forestry
Seasonal growth of gorse and its susceptability to 2,4,5-T and 2,4,5-T/picloram
A trial was established to determine the effectiveness of spraying mature gorse (Ulex europaeus) with 2,4,5-T and 2,4,5-T I picloram at monthly intervals over 12 months.
The effectiveness depended on the stage of growth at the lime of herbicide application. Optimum results occurred when gorse flowering was completed, most seed pods were fully developed, and a new flush of foliage had grown to about 2.5 cm in length. As new foliage grew and matured so the duration of control was reduced. The duration of control did not differ between herbicides.
The pattern of regrowth was related to time of spraying and is a further reflection of the initial spray effectiveness. After the October, December, and January applications, regrowth occurred only as basal sprouts. At all other times, regrowth occurred on all sections of the desiccated stems from the base of the bush to the previous terminal point of the bush.