Selective herbicides for control of hen's eyes (Ardisia crenata) in forests and natural areas.
Hen's eyes (Ardisia crenata Sims) is a shade-tolerant invasive shrub displacing native understory in forests of the Coastal Plain of the southeastern United States. Few studies have explored herbicide effectiveness on A. crenata, with foliar applications of triclopyr amine or triclopyr ester typically referenced as the standard treatments. This study evaluated efficacy of eight foliar herbicide treatments and a nontreated check at three locations at 12 mo after the first treatment (12 MAT1) and 12 mo after the second treatment (12 MAT2) on established (greater than 8-cm high) and seedling (less than 8-cm high) A. crenata. Treatments were four triclopyr formulations: amine, ester, choline, and acid (all at 4.04 kg ae ha-1); imazamox (1.12 and 2.24 kg ae ha-1); flumioxazin (0.43 kg ai ha-1); and triclopyr amine plus flumioxazin (4.04 + 0.43 kg ae ha-1). At 12 MAT1, triclopyr ester, the high rate of imazamox, and triclopyr acid resulted in greater control of established A. crenata than any other herbicide (68%, 66%, and 64%, respectively). At 12 MAT2, all herbicides except flumioxazin resulted in some control of A. crenata. Triclopyr ester, triclopyr acid, and the high rate of imazamox provided 95%, 93%, and 92% control, respectively. Triclopyr choline did not perform as well as the acid or ester formulations, and the tank mix of flumioxazin and triclopyr amine did not improve control over triclopyr amine alone. This study identified triclopyr acid and imazamox (2.24 kg ae ha-1) as new options for A. crenata control and indicated variation in the performance among the four triclopyr formulations.