Seasonal Response of Macartney Rose and Huisache to Herbicides

Abstract

Picloram granules and sprays were applied to Macartney rose (Rosa bracteata Wendl.) and huisache (Acacia farnesiana (L.) Willd.) in the claypan area of Texas. Monthly granule applications to Macartney rose were generally least effective in the summer. Rates of 1, 2, and 3 lb/acre of picloram as granules reduced the canopy 53, 68, and 86% and killed 14, 32, and 57% of the plants, respectively. Foliar sprays of picloram were about equally effective as granules. Huisache was not as highly responsive to picloram as to either granules or soil sprays at rates up to 4 lb/acre. However, picloram at 2 lb/acre as a foliage spray in May or September killed 90% or more of the plants. A 1 lb/acre foliage spray of picloram combined with a 1 lb/acre spray of 2,4,5-T, dicamba, or picloram in the soil also killed 53% or more of the huisache plants.