Chinese tallowtree is an invasive tree found throughout the southeastern United States and in California. Its negative effects can be seen in numerous natural and managed ecosystems, including bottomland hardwood forests, pastures, pine plantations, and along lakes, ponds, streams, and rivers. Despite its troublesome presence for many decades, relatively few effective control strategies are available. Root sprouting following management efforts is a major impediment to successful control. Studies were conducted in Alabama and Louisiana at three locations to test several herbicides for cut stump, basal bark, and foliar individual plant treatment (IPT) methods. Herbicide treatments included triclopyr amine and ester formulations, imazamox, aminopyralid, aminocyclopyrachlor, and fluroxypyr. Data were collected just before leaf senescence at one and two growing seasons after treatment and included Chinese tallowtree foliar cover, number of stump or root collar sprouts, and number of sprouts originating from lateral roots within a 1-m radius of each tree. For the cut stump and basal bark studies, most herbicide treatments prevented sprouting from the stump or root collar region better than they did from the lateral roots. Aminopyralid reduced total sprouting better than all other treatments in the cut stump study. The high rates of aminocyclopyrachlor and fluroxypyr resulted in the highest mortality in the basal bark study. Aminocyclopyrachlor reduced total sprouting better than all other herbicides in the foliar treatment study. Triclopyr amine and ester formulations, which are commercial standards, did not consistently control Chinese tallowtree across these IPT studies. These studies provide some promising treatments to increase the number of effective tools that can be used to manage Chinese tallowtree. Additional research is needed to address the prolific nature of lateral root sprouting following any of these treatment methods.
Nomenclature: Aminocyclopyrachlor; aminopyralid; fluroxypyr; imazamox; triclopyr; Chinese tallowtree, Triadica sebifera (L.) Small.
Management Implications: Chinese tallowtree is an increasing problem across the southeastern United States. However, there is little published research examining effective control methods. We compared several newer herbicides with the commercial standards triclopyr ester and triclopyr amine for foliar, cut stump, and basal bark individual plant treatment (IPT) methods in natural areas. We examined both root collar and lateral root sprouting response to herbicide treatment, which is rarely done in invasive plant studies. We found that aminocyclopyrachlor, aminopyralid, fluroxypyr, and imazamox all controlled Chinese tallowtree similar to, or better than, triclopyr in specific IPT studies. Aminocyclopyrachlor resulted in greater mortality of Chinese tallowtree than triclopyr did in foliar and basal bark studies, whereas aminopyralid was more effective than triclopyr in cut stump studies. Fluroxypyr resulted in greater mortality than triclopyr in cut stump and basal bark studies but not in foliar studies. This research highlights the strong need to continue to evaluate new tools for invasive plant control and the need to continuously collect better data on invasive plant responses to treatment.