Herbicide absorption and translocation patterns were determined following a wet blade method of application to dogfennel stems. Treatment consisted of severing stems with a pruning shear blade containing 5 μl of [14C]-triclopyr or [14C]-clopyralid solution. More than 73 or 82% of applied [14C]-triclopyr or [14C]-clopyralid was absorbed immediately, and uptake increased to more than 90%, 60 min after treatment. Both radiolabeled compounds appeared in the roots as soon as 12 h after treatment. By 48 h, 5 to 7% of the [14C] label was present in the roots, and 7 to 10% was exuded from the roots.

Greenhouse and field studies were conducted to investigate the responses of container-grown dogfennel, multiflora rose, and purple loosestrife to clopyralid or triclopyr applied to plants from a pruning shear blade. Clopyralid or triclopyr was diluted with water to various concentrations and placed on one side of a pruning shear blade in final volumes of either 1 or 5 μl. The shears were then used to sever and treat stems. Results indicated that 20% triclopyr concentrations in 5-μl total volume (360 μg active) gave ≥ 96% reductions of foliar regrowth in dogfennel, multiflora rose, and purple loosestrife 70, 42, and 56 days after treatment (DAT), respectively. The same delivery rate for clopyralid gave 96% dogfennel control 70 DAT. Subsequent visual ratings with multiflora rose (105 DAT) and purple loosestrife (260 DAT) confirmed that early reductions in biomass were good indicators of long-term control.