Abstract

Two studies were conducted to evaluate the influence of herbicides on root initiation and development from stem cuttings of three woody landscape species. In the first experiment, Rhododendron obtusum ‘Hino Crimson’ rooting percentage was suppressed with Rout 3G (oxyfluorfen + oryzalin). Both root quality ratings and root lengths were lower for stem cuttings when herbicides were applied compared to untreated controls. Rooting percentages of Rhododendron × ‘Trouper’ and Gardenia jasminoides ‘August Beauty’ were not affected by herbicide application. Root quality ratings and root lengths were generally lower with Rout 3G, OH-2 3G (oxyfluorfen + pendimethlin), Snapshot 2.5TG (trifluralin + isoxaben), and Southern Weed Grass Control 2.68G (pendimethlin) when compared to untreated controls. In the second experiment, depth of sticking Gardenia jasminoides ‘August Beauty’ cuttings and herbicide treatments were evaluated. Cuttings in Rout 3G and Snapshot 2.5 TG treatments had improved root quality ratings when stuck to a depth of 2.5 cm (1.0 in) compared to 1.3 cm (0.5 in); however, all other herbicide treatments had similar root quality ratings to the untreated controls, regardless of depth of sticking.