Weed Control With Herbicide-Coated or -Blended Fertilizer in ‘August Beauty’ Gardenia

Abstract Prostrate spurge (Euphorbia maculata L.) control and injury to container-grown ‘August Beauty’ gardenia (Gardenia jasminoides Ellis) were evaluated using Ronstar 50WP (oxadiazon) or Pennant 7.8E (metolachlor)-coated or Ronstar 2G (oxadiazon) or Pennant 5G (metolachlor)-blended Nursery Special 12N–2.6P–5.0K (12–6–6) fertilizer. Herbicides were applied at 4 rates, 2.3, 4.5, 9.0, and 18.0 kg ai/ha (2, 4, 8, and 16 lb ai/A) and compared to broadcast and spray applied pre-emergence herbicide applications at 4.5 kg ai/ha (4 lb ai/A). Ronstar (oxadiazon)-coated or -blended Nursery Special at all rates, except 2.3 kg ai/ha (2 lb ai/A) provided similar weed control to the broadcast or spray applied controls. Pennant (metolachlor)-coated or -blended fertilizer controlled spurge only at 18.0 kg ai/ha (16 lb ai/A). Weed control was similar when comparing herbicide formulation (coated vs. blended). Gardenia growth was similar among treatments and no injury symptoms were observed with any treatment.