English Ivy (Hedera helix) Response to Postemergence Herbicides

Abstract

One application of Roundup at 2.2 or 4.5 kg ai/ha (2.0 or 4.0 lb/A) with or without surfactant, Weedar 64 (2.4-D amine) at 1.1 kg ae/ha (1.0 lb/A), Banvel at 0.6 kg ae/ha (0.5 lb/A), or Garlon 3A at 0.6 kg ae/ha (0.5 lb/A) reduced new shoot growth of English ivy 10 weeks after treatment by 46 to 80%. Roundup at 4.5 kg/ha plus non-ionic surfactant was the only single application treatment that reduced older shoot growth of English ivy (41% reduction) 19 weeks after treatment. English ivy outgrew injury from all other single application treatments. Two applications of Weedar 64 completely controlled English ivy. Two applications of Roundup at 4.5 kg/ha (4.0 lb/A), with or without surfactant, eliminated new shoot growth 11 weeks after treatment, and reduced total shoot weight by approximately 60% 15 weeks after treatment. English ivy shoot weight decreased when the rate of Roundup was increased from 2.2. to 4.5 kg/ha (74 versus 92% reduction) 7 weeks after treatment, but adding a non-ionic surfactant did not further reduce shoot weight. Two applications of Banvel or Garlon (52 and 67% reduction, respectively, 7 weeks after treatment) were less effective than two applications of Roundup at 4.5 kg/ha (4.0 lb/A) in reducing English ivy shoot growth.