Twelve‐year‐old ‘Sundrop’ apricot(Prunus armeniacaL.) trees were treated with a single soil application of paclobutrazol (PBZ) at the rate of 2, 4, and 6 g of active ingredient per tree. The chemical was applied as a trunk drench. Regardless of rate, PBZ treated trees had significantly reduced most vegetative growth characteristics and pruning requirements as compared with control trees. A rate of 2 g PBZ/tree effectively controlled vegetative growth for 3 years. Bioassay with broad bean(Vicia fabaL.) confirmed that PBZ was still present in the treated soil almost 3 years after application. The extent of growth suppression of the indicator plants was in direct relation to the treatment rate.