Effect of Preemergent Herbicides on Growth of Dwarf Nandina, Eleagnus, Asiatic Jasmine, Bradford Pear, and Arizona Ash

Abstract

The list of species that are known to tolerate the use of Factor® (prodiamine), a preemergent herbicide, in a containerized production system is limited. Plants of swarf nandina (Nandina domestica `Firepower'), eleagnus (Eleagnus × eggingei), and Asiatic jasmine (Trachelospermum asiaticum) growing in 3.8-L containers were obtained from a local nursery and treated with herbicide treatments to determine effects on growth. Plants were treated with one or two applications of Factor® 65WG at either 0, 1.4, 2.8, or 5.5 kg·ha–1 (0.9, 1.8, or 3.6 kg·ha–1 active ingredient, respectively). The first application was made on 10 Aug. 1995 and the second application was made on 19 Oct. 1995. Plants were grown under 30% Saran shade and watered and fertilized as needed. Plants of Arizona ash (Fraxinus sp.) and Bradford Pear (Pyrus calleryana `Bradford') ptted in 19-L containers were treated with herbicide treatments on 25 Oct. 1995 for fall weed control at a local nursery. Treatments included a single application of Factor® 65WG at either 0, 1.4, 1.8, or 2.8 kg·ha–1 (0.9, 1.2, or 1.8 kg·ha–1 active ingredient, respectively) with or without Gallery® (isoxaben) at 1.2 kg·ha–1 (0.9 kg·ha–1 active ingredient). There was no effect of the herbicide treatments on growth of eleagnus. Herbicide treatments did not affect shoot dry weight and did not have a deleterious effect on shoot length and root dry weight of Asiatic jasmine or affect trunk caliper growth of the two tree species. Factor® did affect the growth of dwarf nandina. Plant height and shoot and root dry weight were not affected. However, plant width was decreased by all Factor® treatments when compared to untreated plants.